Implemented script commands StartCombat, StopCombat, GetTarget.

Also renamed one field of AIWander class because it's not longer
unknown.
printAIPackage: changed field name from Unknown to ShouldRepeat too.
MWScript: updated vmformat.txt, changed opcodes to fix sequence.

Opcodes for StartCombat, StopCombat, GetTarget now follow the last
previous opcode.
Get bk_treasuryreport script to work properly:
 - OnPcEquip needs to be set on *using* any item, not just equipping
 - Handle PcSkipEquip
 - Execute item's script once immediately after setting OnPcEquip
 - Do not set OnPcEquip when an item that has skipped equipping sets pcskipequip back to 0 and gets equipped
some junk removal
Merge remote-tracking branch 'sergeyshambir/startcombat'

Conflicts:
	apps/openmw/mwscript/docs/vmformat.txt