Add grunt lineendings task.

Initially two of the tests were failing on my computer because some
files used ‘\n’ while others used ‘\n’.

I don’t have a preference about which line break character to use, let
me know what your thoughts are re this.
Support end marker <!-- /include -->
Add index.html test and maintain indentation.
Add Haml support.
Add Jade.
Add Sass.
Add less.
Add overwrite test.
Update Readme.