Rewrite of Smarty syntax highlightin

* Only apply smarty syntax patterns within delimeters [#9]
  Resolves syntax highlighting for HTML within a Smarty document.
* Support for both default and custom delimeters [#3, #8]
* More specific scope selectors
Merge pull request #11 from amitsnyderman/syntax-refactor-squash

Rewrite of Smarty syntax highlighting