Refactor TS build and fix testing

This change is largely just moving files with minor tweaks to them to fix,
the rest of the commit is build process changes:

- The addons/ and test/ dirs have been moved to src/
- The build directory has been removed
- TypeScript builds are output in out/, this is where tests are run
- The demo now relies on the dist/ build which is performed as part of ./bin/build
- Addons are now shipped under the ./build directory

src/addons/fullscreen/fullscreen.css

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+.xterm.fullscreen {
+    position: fixed;
+    top: 0;
+    bottom: 0;
+    left: 0;
+    right: 0;
+    width: auto;
+    height: auto;
+    z-index: 255;
+}

src/addons/fullscreen/fullscreen.js

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+/*
+ * Fullscreen addon for xterm.js
+ *
+ * Implements the toggleFullscreen function.
+ *
+ * If the `fullscreen` argument has been supplied, then
+ * if it is true, the fullscreen mode gets turned on,
+ * if it is false or null, the fullscreen mode gets turned off.
+ *
+ * If the `fullscreen` argument has not been supplied, the
+ * fullscreen mode is being toggled.
+ */
+(function (fullscreen) {
+  if (typeof exports === 'object' && typeof module === 'object') {
+    /*
+     * CommonJS environment
+     */
+    module.exports = fullscreen(require('../../xterm'));
+  } else if (typeof define == 'function') {
+    /*
+     * Require.js is available
+     */
+    define(['../../xterm'], fullscreen);
+  } else {
+    /*
+     * Plain browser environment
+     */
+    fullscreen(window.Terminal);
+  }
+})(function (Xterm) {
+  var exports = {};
+
+  exports.toggleFullScreen = function (term, fullscreen) {
+    var fn;
+
+    if (typeof fullscreen == 'undefined') {
+      fn = (term.element.classList.contains('fullscreen')) ? 'remove' : 'add';
+    } else if (!fullscreen) {
+      fn = 'remove';
+    } else {
+      fn = 'add';
+    }
+
+    term.element.classList[fn]('fullscreen');
+  };
+
+  Xterm.prototype.toggleFullscreen = function (fullscreen) {
+    exports.toggleFullScreen(this, fullscreen);
+  };
+
+  return exports;
+});

src/addons/fullscreen/package.json

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+{
+  "name": "xterm.fullscreen",
+  "main": "fullscreen.js",
+  "private": true
+}