Reset cache after save

Usually this is not necessary, due to the way php5 deals with objects. If there is a static the cache, the object in the cache is the same as the updated one - thus any changes should be already there. However, this is indeed problematic if you have an entity serialized, e.g. form storage and do an update then + in some other cases as well.

The same issue applies to core though, at least for node_save(). See the related issue #651240: Allow modules to react to changes to an entity.

I just ran over another issue with the static cache: Clearing the cache in the delete hook doesn't properly work, e.g. calling menu_rebuild() - as in the hook the static cache is still available. That already caused issues in profile2.

The same though applies to the 'insert' and 'update' hooks - the changes should already be applied once the hooks are invoked. Thus we need to clear the cache before invoking the hook.

Follow-up: Create an issue to fix static-cache clears in core.