Minor bug fixes

Hi Marijn,

@Develooper spotted a few minor problems with the Smarty mode (both version 2 and 3). This pull request fixes the following:
- escaped quotes within a string no longer incorrectly close the string's highlighting.
- parentheses are now highlighted consistently as "brackets" class (they'd default to "tag" sometimes); neither these nor variable qualifiers (followed by |) are now affected by whitespace.

Thanks!

Ben