Allow keyboard nav in multiSelect grids

Updated selectionProvider to allow the use of up/down arrow keys for
navigation and selection in multi-selection grids.
Grunt 'default', 'prod' and 'version' tasks run karma unit tests first and if tests are failing build will fail. Currently i see that 4 unit tests are failing. Once ng-grid core team agrees for my PR i will fix unit tests.
Removed unnecessary karma option 'keepalive'
Missed to check-in karma config file
Merge pull request #304 from ajbenton/master

Update multi-select grid key navigation behavior
Merge pull request #310 from skusunam/master

Run Karma unit tests as part of default\prod\version Grunt tasks (Issue #309)
Fix column sorting when called via options.sortBy API
Merge pull request #314 from tcrimi/master

Fix column sorting when called via options.sortBy API
Merge branch 'master' of https://github.com/angular-ui/ng-grid into bugfixes
fixing issue #302

also adding the state for toggleSelectAll to the beforeSelection and
AfterSelectionChanged events as the second parameter. see issue #270