Redirect folks to new Team Repo

- now point folks to Knockout-Contrib repo
selectionService: toggleSelectAll performance enhancement

Batch add items to the selectedItems array instead of adding them one by one.
Prevents duplication of the selection column.

Added a check to make sure the selection column doesn't exist before adding it.
Updated Links in readme

The links in the readme were giving a 404. Since it looks like the project had moved, I updated the links to the knockout-contrib org  (from the ericbarnard org) and they appear to work correctly now.
Updating readme to correct link

Found one more link -- the Custom Cell Template Library wasn't pointing to the knockout-contrib link.
Merge remote-tracking branch 'upstream/master'
columnsInititalization fix + selection fixes me + selection fixes from jrsearles
Removed check for index (bug fixed)
made 'SELECTED_PROP' as observable + fix issue when item is removed (unselected) from selectedElements collection manually
Add bootstrap tab plugin and row selection plugin
Merge branch 'master' of https://github.com/huer12/KoGrid
Merge branch 'master' of https://github.com/SeanKilleen/KoGrid