Added .erb and .haml to file extensions

When developing Ruby (RoR) apps the file extension .erb (eRuby) and .haml are often used for the views and even the css files can contain embedded ruby code. Therefore ColorHighlighter should highlight the color in these files, too.
Merge pull request #146 from xGhOsTkiLLeRx/master

Added .erb and .haml to file extensions