Allow the setting of the grid size in Trebuchet.

This allows the user to set the launcher grid size up to 11x10.
Default behavior is unchanged.
If too large a size is chosen then icons will be cut off or overlap.

Change-Id: I3c22360bf1e39a9795a5a7dde0bd4c8b335f1902
Merge "Allow the setting of the grid size in Trebuchet." into cm-10.1