Add noUnusedLocals tsconfig flag, fix issues

Two parts were commented out:
- _writeStopped: This is because _xoffSentToCatchUp references this variable
  and the feature is sort of half implemented/disabled.
- _clearChar: This is because some comments still reference this, it's part
  of the work needed to do better line redrawing.

src/renderer/BaseRenderLayer.ts

@@ -4,11 +4,11 @@
  */
 
 import { IRenderLayer, IColorSet, IRenderDimensions } from './Types';
-import { CharData, ITerminal, ITerminalOptions } from '../Types';
+import { CharData, ITerminal } from '../Types';
 import { DIM_OPACITY, INVERTED_DEFAULT_COLOR } from './atlas/Types';
 import { CHAR_ATLAS_CELL_SPACING } from '../shared/atlas/Types';
 import { acquireCharAtlas } from './atlas/CharAtlas';
-import { CHAR_DATA_WIDTH_INDEX, CHAR_DATA_CHAR_INDEX } from '../Buffer';
+import { CHAR_DATA_CHAR_INDEX } from '../Buffer';
 
 export abstract class BaseRenderLayer implements IRenderLayer {
   private _canvas: HTMLCanvasElement;

src/renderer/CursorRenderLayer.ts

@@ -3,11 +3,10 @@
  * @license MIT
  */
 
-import { CHAR_DATA_WIDTH_INDEX, CHAR_DATA_CODE_INDEX, CHAR_DATA_CHAR_INDEX } from '../Buffer';
-import { GridCache } from './GridCache';
-import { FLAGS, IColorSet, IRenderDimensions } from './Types';
+import { CHAR_DATA_WIDTH_INDEX } from '../Buffer';
+import { IColorSet, IRenderDimensions } from './Types';
 import { BaseRenderLayer } from './BaseRenderLayer';
-import { CharData, IBuffer, ICharMeasure, ITerminal, ITerminalOptions } from '../Types';
+import { CharData, ITerminal } from '../Types';
 
 interface ICursorState {
   x: number;
@@ -26,7 +25,6 @@ export class CursorRenderLayer extends BaseRenderLayer {
   private _state: ICursorState;
   private _cursorRenderers: {[key: string]: (terminal: ITerminal, x: number, y: number, charData: CharData) => void};
   private _cursorBlinkStateManager: CursorBlinkStateManager;
-  private _isFocused: boolean;
 
   constructor(container: HTMLElement, zIndex: number, colors: IColorSet) {
     super(container, 'cursor', zIndex, true, colors);

src/renderer/LinkRenderLayer.ts

@@ -3,11 +3,8 @@
  * @license MIT
  */
 
-import { ILinkHoverEvent, ITerminal, ILinkifierAccessor, IBuffer, ICharMeasure, LinkHoverEventTypes } from '../Types';
-import { CHAR_DATA_ATTR_INDEX } from '../Buffer';
-import { GridCache } from './GridCache';
-import { FLAGS, IColorSet, IRenderDimensions } from './Types';
-import { INVERTED_DEFAULT_COLOR } from './atlas/Types';
+import { ILinkHoverEvent, ITerminal, ILinkifierAccessor, LinkHoverEventTypes } from '../Types';
+import { IColorSet, IRenderDimensions } from './Types';
 import { BaseRenderLayer } from './BaseRenderLayer';
 
 export class LinkRenderLayer extends BaseRenderLayer {

src/renderer/Renderer.ts

@@ -3,12 +3,10 @@
  * @license MIT
  */
 
-import { CHAR_DATA_WIDTH_INDEX, CHAR_DATA_CHAR_INDEX } from '../Buffer';
 import { TextRenderLayer } from './TextRenderLayer';
 import { SelectionRenderLayer } from './SelectionRenderLayer';
 import { CursorRenderLayer } from './CursorRenderLayer';
 import { ColorManager } from './ColorManager';
-import { BaseRenderLayer } from './BaseRenderLayer';
 import { IRenderLayer, IColorSet, IRenderer, IRenderDimensions } from './Types';
 import { ITerminal } from '../Types';
 import { LinkRenderLayer } from './LinkRenderLayer';

src/renderer/SelectionRenderLayer.ts

@@ -3,10 +3,8 @@
  * @license MIT
  */
 
-import { IBuffer, ICharMeasure, ITerminal } from '../Types';
-import { CHAR_DATA_ATTR_INDEX } from '../Buffer';
-import { GridCache } from './GridCache';
-import { FLAGS, IColorSet, IRenderDimensions } from './Types';
+import { ITerminal } from '../Types';
+import { IColorSet, IRenderDimensions } from './Types';
 import { BaseRenderLayer } from './BaseRenderLayer';
 
 export class SelectionRenderLayer extends BaseRenderLayer {

src/renderer/TextRenderLayer.ts

@@ -5,7 +5,7 @@
 
 import { CHAR_DATA_ATTR_INDEX, CHAR_DATA_CODE_INDEX, CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX } from '../Buffer';
 import { FLAGS, IColorSet, IRenderDimensions } from './Types';
-import { CharData, IBuffer, ICharMeasure, ITerminal } from '../Types';
+import { CharData, ITerminal } from '../Types';
 import { INVERTED_DEFAULT_COLOR } from './atlas/Types';
 import { GridCache } from './GridCache';
 import { BaseRenderLayer } from './BaseRenderLayer';
@@ -15,7 +15,7 @@ import { BaseRenderLayer } from './BaseRenderLayer';
  * when the character changes (a regular space ' ' character may not as it's
  * drawn state is a cleared cell).
  */
-const OVERLAP_OWNED_CHAR_DATA: CharData = [null, '', 0, -1];
+// const OVERLAP_OWNED_CHAR_DATA: CharData = [null, '', 0, -1];
 
 export class TextRenderLayer extends BaseRenderLayer {
   private _state: GridCache<CharData>;
@@ -239,13 +239,13 @@ export class TextRenderLayer extends BaseRenderLayer {
    * @param x The column of the char.
    * @param y The row of the char.
    */
-  private _clearChar(x: number, y: number): void {
-    let colsToClear = 1;
-    // Clear the adjacent character if it was wide
-    const state = this._state.cache[x][y];
-    if (state && state[CHAR_DATA_WIDTH_INDEX] === 2) {
-      colsToClear = 2;
-    }
-    this.clearCells(x, y, colsToClear, 1);
-  }
+  // private _clearChar(x: number, y: number): void {
+  //   let colsToClear = 1;
+  //   // Clear the adjacent character if it was wide
+  //   const state = this._state.cache[x][y];
+  //   if (state && state[CHAR_DATA_WIDTH_INDEX] === 2) {
+  //     colsToClear = 2;
+  //   }
+  //   this.clearCells(x, y, colsToClear, 1);
+  // }
 }

src/renderer/atlas/CharAtlas.ts

@@ -6,7 +6,6 @@
 import { ITerminal } from '../../Types';
 import { IColorSet } from '../Types';
 import { ICharAtlasConfig } from './Types';
-import { isFirefox } from '../../shared/utils/Browser';
 import { generateCharAtlas, ICharAtlasRequest } from '../../shared/atlas/CharAtlasGenerator';
 import { generateConfig, configEquals } from './CharAtlasUtils';
 

src/renderer/atlas/CharAtlasUtils.ts

@@ -4,7 +4,6 @@
  */
 
 import { ITerminal } from '../../Types';
-import { ITheme } from 'xterm';
 import { IColorSet } from '../Types';
 import { ICharAtlasConfig } from './Types';