(svn r12554) [NoAI] -Codechange: add more typing information.

(svn r12552) [NoAI] -Change: do not force the use of StringIDs when setting errors.

(svn r12551) [NoAI] -Fix: remove unneeded AIObject:: (don't use AIObject:: inside the AIObject class ;))

(svn r12544) [NoAI] -Codechange: do not force dependency on OTTD internal strings when defining errors.

(svn r12539) [NoAI] -Fix: when you take over an AI, the game no longer crashes when a new AI starts again

(svn r12538) [NoAI] -Codechange: introducing fiber.hpp, a class to have fibers in your application via either Windows Fibers, or via thread.h
[NoAI] -Codechange: rewritten ai_threads.cpp, to work with Fiber class. Reduces code duplication, and should fix all the stupid asserts we had with newgames and dying AIs
-NOTE: now my head spins.. 24 hours of working with threads/fibers is bad for health :p Tnx glx for the testing!

(svn r12530) [NoAI] -Fix r12528: missing 'public' statement gives funny effects (tnx glx)

(svn r12529) [NoAI] -Change: split thread.cpp into 4 files, one for each OS

(svn r12528) [NoAI] -Change: rewrote most of the internal ThreadObject to make it a bit more readable
[NoAI] -Change: when a ThreadObject is created, the thread is really created, and not delayed until some sub-function is called
[NoAI] -Change: renamed AutoResetEvent to ThreadSemaphore, as that is what is really is.. AutoResetEvent didn't really give a clue what it was ;)

(svn r12527) [NoAI] -Fix: only the first failing WrightAI could change its name to show it failed