Improvements to AC calculations & display & others (#1751)

* Fixed issues with checking AC for TotalAC item types.
* Added data attribute to suppress a character's dexterity bonus.
* Added warning if trying to change weapon when holding a cursed weapon.
* Support weapons and magic item attacks that use multiple power charges.
* Added ac combination rules to MI database data specifications.
* Fixed ac support for magic helms.
* Support the item charge type 'single-uncharged' for charged items with non-standard discharging mechanisms.
* Display the ac mod effect of each valid item on the Check AC dialog.
* Fix --mod-weap command selection of specified weapons for mod-ing.

Author: DameryDad