Thunderbrd

Just a test

[*]New Promotion: By the Horns: +15% chance to subdue, tech prereq of Persistence Hunting, Unitcombat prereq of Weapon: Hand to Hand

[*]Fixes overflows taking place in the calculation of Espionage Mission costs.

[*]Corrects a promotion update issue on upgrading units - in the process I've found a place that really needs streamlining, CvUnit::doSetFreePromotions... wow that's not efficient at all. I did not correct that but just the inaccuracy of how it was potentially overridden later in the upgrade process, which is another major timing inefficiency that I should probably do something to keep from happening - this free promo is assigned on init, removed because the original doesn't have it, and the...

[*]Small tweak to last coding change to adjust bracketing for clarity of intent.

[*]confirms removal of debug dll - if you need it, compile it from the MakeDLLDebug.bat file in the tools folder

[*]Corrects an old bug I probably left behind in getUnitProductionModifier in traits