Simplify Default Grunt Task

Now just runs sass:dev and then watches for changes. Run grunt build
for the autoprefixing and compression.
Source Maps by Default

This commit introduces dependency on Sass 3.3, as it introduces source
maps.

gem update
sass —version # you got 3.3 right?
cd revolution/_build/templates/default
grunt sass:map # just compile sass with source maps
grunt #compile sass with source maps and watch for changes
Removing grunt ship
Simplify Default Grunt Task, Source Maps by Default

* origin/pr/11211:
  Removing grunt ship
  Source Maps by Default
  Simplify Default Grunt Task