Disabled gamma settings from being applied if shaders are disabled, hopefully this should prevent desktop-wide gamma alteration

Misc 1.7.1

Change Notes:  
* Lower level of enemies in bandit fortress vault  
* Reduce the frequency at which rares take talents in the Combat Techniques tree, potentially alleviating a concern that rares have too high accuracy in 1.7  
* Minimize use of raw talent level where effective should be used and has precedent for use  


See merge request !667

Added a way for the game to try and load (and fix) savefiles with errors (usualy due to data that should not have been saved). It is likely to work in many instances, but not guaranted.

Multiple stacks of Retch on the ground have disminishing returns on the healing; to alleviate NPC necromancers summoning lots of ghouls and being basically on infinite regen mode :)

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

new Header UI class