FIX: Enable compiling without manually #defining SDL for MinGW
FIX: Better server timing (TurfIt)
FIX: Division by zero error, causing crashes in some instances.
FIX: Further division by zero errors, causing crashes in some instances.
Merge branch '11.x' into 12.x
Merge branch '12.x' into devel-new
Merge branch 'devel-new' into 112.5-merge

Conflicts:
	simworld.cc

NOTE: This does *not* merge the server timing improvement, as the code is too different for this to be done without understanding the intention of the code in detail. There may well be a Standard patch to the latest code which will be based on that and will apply here.