Update the on_pre_use for Vault to check for a shield only. The action only uses the shield, so we don't need to check for sling and ammo as well.

Allows Steady Shot triggered via Shoot to apply Marked even if Master Marksman is not known, just as using the talent manually would.

This hook/callback allows modifying talent tactical table. It is useful for sustains that modify other talents' behavior, like Arcane Combat, and allows more fine-grained AI management.
This modification may significantly buff Arcane Blade npcs.

http://forums.te4.org/viewtopic.php?f=42&t=51743

Prevent use of raw talent level where tome has a precedent to use effective and it doesn't make sense to use raw

IMPORTANT: removeEffectsSustainsTable, removeEffectsSustainsTable, removeEffectsSustainsTable and removeEffectsSustainsTable now take a first src parameter. Addons need updating or will explode!