Enable Dual-classing into Kits

Dual-class into Kit

Installation Order:
* This mod should NOT be installed BEFORE any mod that adds new kits.
* This mod should NOT be installed BEFORE any mod that alters race(MGSRCREQ.2da/CLSRCREQ.2da) or dualclass(DUALCLAS.2da/ABDCDSRQ.2da) restrictions.
* This mod should NOT be installed BEFORE any mod that alters string references in CLASTEXT.2da, KITLIST.2da, or RACETEXT.2da/SODRACE.2da.

Limitations:
* Class/Kit description in the record screen will display the description of the unkitted second class.
* Level-up proficiency selection is still dictated as if an unkitted second class.
* Specialists Mages will not recieve their bonus spell slots. (Fix included in second component.)
(These are all the same issues that occur when you manually change the second-class kit through EEkeeper/Near Infinity)

Compatibility:
* BGEE, BGSOD, BG2EE, all v2.3 or later.
* Supports multiple RACTTEXT.2da files, read from CAMPAIGN.2da.
* The entire Chargen Class Selection portion of UI.menu is replaced, if I knew better how to make the changes I would.
* The Chargen Mage Spell Selection portion has a very simple edit, small chance of conflict with other UI mods.