Fix #359 - Introduce build system based on Gulp

- Add Gulp and new dependencies to `package.json`
- Add `gulpfile.js` with four tasks:
    - `tsc`: For building TypeScript sources
    - `bundle`: For bundling JavaScript modules in a monolith
    - `sorcery`: For resolving the source map chains back to the original TypeScript files
    - `build` (`default`): Runs the whole `tsc` → `bundle` → `sorcery` chain
- Clean up `Dockerfile`, since `cpio` is not needed any more
- Clean up not needed dependencies from `package.json`
- Remove `bin/build`
- Update `bin/release` to use `npm run build` instead of `./bin/build`

bin/build

@@ -1,36 +0,0 @@
-#! /usr/bin/env bash
-
-set -e
-
-# $BUILD_DIR should default to "build"
-BUILD_DIR=${BUILD_DIR:=build}
-
-# Create the build directory
-mkdir -p $BUILD_DIR
-
-
-# Clean lib/* to prevent confusion if files were deleted in src/
-rm -rf lib/*
-
-# Build all TypeScript files (including tests) to lib/
-tsc
-
-# Concat all xterm.js files into a single file and output as a UMD to $BUILD_DIR/xterm.js
-browserify ./lib/xterm.js --standalone Terminal --debug --outfile ./$BUILD_DIR/xterm.js
-cat ./$BUILD_DIR/xterm.js | exorcist ./$BUILD_DIR/xterm.js.map -b ./$BUILD_DIR > ./$BUILD_DIR/xterm.temp.js
-rm ./$BUILD_DIR/xterm.js
-mv ./$BUILD_DIR/xterm.temp.js ./$BUILD_DIR/xterm.js
-
-# Resolve the chain of sourcemaps so that ./$BUILD_DIR/xterm.js.map points at ./src
-sorcery -i $BUILD_DIR/xterm.js
-
-# Copy all CSS files from src/ to $BUILD_DIR/ and lib/
-cd src
-find . -name '*.css' | cpio -pdm ../$BUILD_DIR
-find . -name '*.css' | cpio -pdm ../lib
-cd ..
-
-# Copy addons from lib/ to $BUILD_DIR/
-cd lib/addons
-find . -name '*.js' | cpio -pdm ../../$BUILD_DIR/addons
-cd ../..

bin/prepare-release

@@ -21,7 +21,7 @@ CURRENT_BOWER_JSON_VERSION=$(cat bower.json \
 
 # Build xterm.js into `dist`
 export BUILD_DIR=dist
-./bin/build
+npm run build
 
 # Update AUTHORS file
 sh bin/generate-authors