- Version update to 1.11
Engine Features
* Players now have their own private stash in addition to the
shared stash.
* Expanded the 'no_stash' Item variable to account for having
multiple stashes.

Engine Fixes
* Fix bug where items could be dragged from the vendor window and
dropped in the opposite vendor tab.
* Fix bug that caused item max_quantity to be reset when attempting
to append an item definition.
* Fix bug where Powers with 'replace_by_effect' would still use
properties from the parent power, such as animation state.

- Removed post/postun macros since they are no longer needed with
Leap 42.3 going end-of-life.