Add Sass.load_paths entry to help absolute @import paths

Nice feature added in Sass 2.3 - see nex3/sass@5c93cbfe

This should resolve thomas-mcdonald/bootstrap-sass#259 better than making users manually adding a load_paths entry.
Added license to gemspec
Merge pull request #266 from petedmarsh/add-license-to-gemspec

Added license to gemspec
Improved script to do all necessary actions for upgrade.

Now automatically takes care of path changes for the includes in bootstrap.scss and responsive.scss (From #258)
Update to 2.2.2 from jlong/sass-twitter-bootstrap#44
Bump version numbers to 2.2.2.0
Merge pull request #270 from trisweb/tristan_2.2.2

Update bootstrap to 2.2.2 (our 2.2.2.0) :shipit:
use simple github notation in sass_head.gemfile
Merge pull request #275 from timoschilling/patch-1

use simple github notation in sass_head.gemfile
change typo in "Versioning" explanation 

change the "y" to a "z" when explaining the patch version
Merge pull request #279 from theverything/patch-1

change typo in "Versioning" explanation
Update rake:debug with file locations
Draft contributing document
Updated README.md to add syntax highlighting
Merge pull request #283 from parndt/patch-1

Updated README.md to add syntax highlighting
Use asset pipeline if defined Sprockets instead of checking for Rails version
Update $dropdownLinkColorActive in _variables.scss

Update $dropdownLinkColorActive from $dropdownLinkColor to $white.

Reference Issue:
https://github.com/thomas-mcdonald/bootstrap-sass/issues/282
Merge pull request #286 from whatasunnyday/update-var-name

Update $dropdownLinkColorActive in _variables.scss
Merge pull request #284 from ssherif/master

Change the checks for Asset Pipeline from the
version of Rails to the presence of Sprockets
Merge pull request #260 from trisweb/tristan_259_add_global_sass_load_path

Add Sass.load_paths entry to help our absolute @import paths