Fix bootstrap to not be double imported.

Fixes #54

Changes:
* add rspec test to ensure precompiled CSS does not break selector limit
include css test
fix respond require statement
fix default rake task
revert to master branch
Merge branch 'fix-sass-import'

* fix-sass-import:
  revert to master branch
  fix default rake task
  fix respond require statement
  include css test
  Fix bootstrap to not be double imported.