fix(build): add webapp upstream features and better coffee

Merge changes from generator-webapp and better support for coffee/js
tasks

BREAKING CHANGES: Coffee support in the Gruntfile is only added when the
coffee flag is set. Otherwise, JS is used
Fixes: #35, #440
Merge pull request #471 from eddiemonge/upgrunt

fix(build): add webapp upstream features and better coffee
fix(build): use test-specifc jshintrc

jshint would not pick up the correct test-specific `.jshintrc` file and throw a
warning during the build process if it wasn't specified explictly.

closes #477
feat(gen): add Compass support to the initialization process

Twitter Bootstrap with the Compass CSS Authoring Framework question will show up only if both Compass and Bootstrap have both been enabled