Upgrade grunt-bower-task to 0.4.0

This upgrades grunt-bower-task's version of bower, which fixes the
problem with the tmp package.
Add multiselect functionality
Fix multiselect bugs

Make selection contain the contents of rows, rather than the row objects
themselves, and make a new Ember.Set for each EmberTableComponent

Closes #192
Compile dist files
Fix another multiselect bug
Improvements to docs pages

* Add community examples page
* Clean up dependencies list
* Remove some unhelpful descriptions
* Reorganize pages
* Add migration guides page
* Fix sidebar covering footer