Use webpack to build files and webpack-dev-server for testing (#1068)

* Create a separate entry point for webpack

Created a webpack entry point for KaTeX, which imports katex.less. As
flow[1] and jest[2] doesn't support CSS modules natively, a separate
entry point is used and it is not flowtyped.

[1] https://gist.github.com/lambdahands/d19e0da96285b749f0ef
[2] https://facebook.github.io/jest/docs/en/webpack.html

* Use webpack to build files

* Made webpack.config.js export valid webpack configuration
* Use:
browserify -> webpack
babelify -> babel-loader
UglifyJS CLI -> UglifyJsPlugin
Less CLI -> less-loader
cleancss -> cssnano in css-loader
build/fonts -> file-loader
* Inline CSS(Less) using style-loader and export them using
ExtractTextPlugin
* Add `watch` npm script calling `webpack --watch`

* Improve local testing(webpack-dev-server)

* Made webpackDevServer export a valid webpack configuration
* Compile Less and inline CSS using less-loader and style-loader
* Instead of copying files serve files from /static and use file-loader
* Remove old server.js and its dependencies

* Use webpack-dev-server in Screenshotter

* Include contrib in webpack-dev-server

+ Moved common configurations to webpack.common.js

* Rename webpackDevServer.js to webpack.dev...

to be consistent, avoid confusion with webpack-dev-server and follow
webpack configuration naming convention.

* Remove unnecessary conditional output.path

* Use map instead of reduce

+ Add comments regarding function arguments

* Remove unnecessary mkdir and clean build/* before build

* Use katex as external dependency instead of global variable in contrib

Fixes #692.

* Unblock codes as they are built as a module

* Update package-lock.json

* Add comments regarding devServer option

* Lint renamed webpack.dev.js

a0d8b33

* Export ES6 module and expose its default export

* Revert "Browserify hotfix (#1057)"

This reverts commit f6b509123b.

* Enables colors on the console when running the dev server in Screenshotter

* Add context to webpack configuration

Allows webpack to be run from other directories

* Move `rm -rf build/*` to npm scripts

* Check dependencies before build

* Move UglifyJsPlugin into config creation

* Let webpack handle ES6 modules

Do not transform modules to commonjs in Babel. However Jest doesn't not
support ES6 modules, so transfrom modules to commonjs when NODE_ENV is
`test`.

* Add documentation on testing in IE 9 and 10 using webpack-dev-server

Changed version range to include IE-compatible version

dockers/Screenshotter/screenshotter.js

@@ -3,7 +3,6 @@
 
 const childProcess = require("child_process");
 const fs = require("fs");
-const http = require("http");
 const jspngopt = require("jspngopt");
 const net = require("net");
 const os = require("os");
@@ -12,7 +11,9 @@ const path = require("path");
 const selenium = require("selenium-webdriver");
 const firefox = require("selenium-webdriver/firefox");
 
-const app = require("../../server");
+const webpack = require('webpack');
+const webpackDevServer = require("webpack-dev-server");
+const webpackConfig = require("../../webpack.dev");
 const data = require("../../test/screenshotter/ss_data");
 
 const dstDir = path.normalize(
@@ -194,7 +195,9 @@ function startServer() {
         return;
     }
     const port = Math.floor(Math.random() * (maxPort - minPort)) + minPort;
-    const server = http.createServer(app).listen(port);
+    const compiler = webpack(webpackConfig);
+    const server = new webpackDevServer(compiler,
+        webpackConfig[0].devServer).listen(port);
     server.once("listening", function() {
         devServer = server;
         katexPort = port;
@@ -315,7 +318,7 @@ function findHostIP() {
 
     // Now we need to find an IP the container can connect to.
     // First, install a server component to get notified of successful connects
-    app.get("/ss-connect.js", function(req, res, next) {
+    devServer.app.get("/ss-connect.js", function(req, res, next) {
         if (!katexURL) {
             katexIP = req.query.ip;
             katexURL = "http://" + katexIP + ":" + katexPort + "/";