Remove NSPICTPboardType from pasteboard types.

NSPICTPboardType is deprecated. Mac OS will translate
pasted images of that type to a different image format.

Change-Id: Id7a68509615816a852abf1c11a70f0f0c862f0f2
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>