Closes #646

Issue #626

* Remove ":" from electricChars
* Add compareStates function
* Add keyword "using"
* Fix anonymous type

This mode is based very heavily upon the javascript mode.

It is not part of the set of styled classes.

Autolinks were not being displayed as such in the editor, changed
'linkhref' to 'link' in line 72 to fix it.

Added support for GFM double bracket links. '[[link]]' is now displayed
correctly as a link by the editor.

Added coloring support for latex formulas, usage of
- "$formula$",
- "$$formula$$",
- "\( formula \)", and
- "\[ formula \]"
will now be highlighted with the same coloring used for strings.

Closes #560