Add some missing MooTools vars

`More`, `Form`, `$HEX`, `$HSB` and `$RGB`.
Ref GH-1560.
Test for newly added MooTools vars

Close GH-1560
Add basic support for ES6 TemplateLiterals

These changes are intended to prevent jshint from choking on template literals when
esnext mode is enabled. It has been written to support a sub-lexing process to allow
for further linting in the future. At this time it does not support escaped string
characters with backslashes, due to my limited knowledge of the template literal
syntax.

I am hopeful that this will pave the way for doing more useful linting with this
construct, and to allow jshint to be used in applications which make use of this
language feature.
Merge pull request #1561 from bootleq/mootools

Update the list of MooTools variables.
Merge pull request #1563 from caitp/issue-1219

Add basic support for ES6 TemplateLiterals
Strip comments in JSON by parsing instead of regex

Using regex for this is just too fragile.

I've changed it out to use the strip-json-comments module instead: https://github.com/sindresorhus/strip-json-comments

Example of where the existing one will fail:

    console.log(removeComments('{"a":"b//c"}'));
    //=> {"a":"b
Redo #1548 for the master branch

Switch statement within loop doesn't recognize 'continue' if case is
wrapped in { }
Merge pull request #1582 from Famlam/issue1318master

Redo #1548 for the master branch
Merge pull request #1580 from sindresorhus/strip-json-comments-master

Strip comments in JSON by parsing instead of regex
Allow expressions with a comma in switch case condition

The ES5 grammar specifies that the `case` keyword should be followed by an
expression (http://www.ecma-international.org/ecma-262/5.1/#sec-A.4) and that
an expression can consist of a comma-separated list of sub-expressions
(http://www.ecma-international.org/ecma-262/5.1/#sec-A.3), so the JSHint parser
should accomodate these commas.
Merge pull request #1588 from jonahkagan/expression-with-comma-in-case-master

Expression with comma in case master