Update tutorials and ngdoc for clarity

Update tutorial for filtering to provide an example of setting
the filter programmatically.

Update the ngDoc for ui.grid:GridOptions to mark functions as
@methodOf rather than @propertyOf, which should correctly split
these into the methods section of the ui-grid.info site.

Update the ngDoc for ui.grid:GridColumns to break the properties
out into separate ngDoc blocks, which should make them more easily
visible in the ui-grid.info site.  Mark these also as @propertyOf
ui.grid:GridOptions.columnDefs, which should result in these
properties also being visible on columnDefs.
ngDoc updates, focusing on columnDefs

A pass through each module looking for settings that are set
in columnDefs, and completing ngDoc updates for each.
Merge pull request #1457 from PaulL1/documentation-updates

Updates to ngDoc and tutorial
Merge pull request #1 from angular-ui/master

Merge to update with master