Upgrade the source to use ES6 syntax including classes, import and static properties (#679)

* Add babel transform-class-properties to have static class properties

* Upgrade Lexer and Parser files to use ES6 classes

* Update eslint max line length to 90 character (more indent because of using ES6 classes)

* Upgrade eslint and jasmin to support ES stage-2 features

* Use static properties to place constants near their functions

* Migrate all remaining sources to ES6 syntax

* Increase eslint max line length to 84

* Remove non-babelified endpoint in dev server.js

* Clean up server.js functions after removing browserified

* Make screenshotter not to use babel endpoint as we babelify everything now

src/environments.js

@@ -1,8 +1,6 @@
 /* eslint no-constant-condition:0 */
-const parseData = require("./parseData");
-const ParseError = require("./ParseError");
-
-const ParseNode = parseData.ParseNode;
+import { ParseNode } from "./parseData";
+import ParseError from "./ParseError";
 
 /**
  * Parse the body of the environment, with rows delimited by \\ and
@@ -67,7 +65,6 @@ function parseArray(parser, result, style) {
  *  - positions: the positions associated with these arguments from args.
  * The handler must return a ParseResult.
  */
-
 function defineEnvironment(names, props, handler) {
     if (typeof names === "string") {
         names = [names];