Upgrade children-of-ie to toolkit

Children of IE was merged into Toolkit which is a collection of tools
and plugins
Merge pull request #7 from scottkellum/master

Remove Children of IE and add Toolkit which Children of IE was rolled into
Re-order plugins list.
Added more finely-tuned configuration of Rack::Session::Cookie for longer timeouts and improved security.
Added Toolkit test.
Bump gems, fix import issue with Neat, add Harsh and Toolkit to footer copy.
Improved and refactored import_plugin method.
Added color-schemer, css-slideshow, fancy-buttons, modular-scale, responsive-sass, and sassy-math gems.
Added tests for new plugins. Added new plugins to footer copy.
Added Salsa.
Merge remote-tracking branch 'upstream/master'