Adds .sass-cache to gitignore
Updates SwatchMaker's Makefile and README

Adds tasks to work with sass-based bootstrap and themes (sass-bootstrap, sass-bootswatch and sass-default) and creates two new tasks [sass-]theme and [sass-]all-themes to build themes without having to manually move files around.
Adds scss versions of all themes
Fix sass-default task
Adds SwatchMaker scss skeletons and generators