Bulk close for 1.4.5

This implementation looks quite problematic.

The Google APIs offer an update endpoint (example, for Users: ) whose description states:

This method supports patch semantics, meaning that you only need to include the fields you wish to update. Fields that are not present in the request will be preserved, and fields set to null will be cleared.

For repeating fields that contain arrays, individual items in the array can't be patched piecemeal; they must be supplied in the request body with the desired values for all items.

This translates to the impossibility to manage AttributeDelta#valuesToRemove.