Fix a problem with two concurent 'round to multiple of basic simulation

Fix a problem with two concurent 'round to multiple of basic simulation
time' code paths. The problem may lead to skipped fdm updates at very high
frame rates. The most visible effect of that was that the aircraft
slips backwards wrt the forward moving carrier.
Remove unused stuff.

Modified Files:
	configure.ac projects/VC7.1/FlightGear.vcproj
	projects/VC8/FlightGearLib.vcproj src/Cockpit/cockpit.cxx
 	src/FDM/Makefile.am src/FDM/flight.cxx src/FDM/flight.hxx
 	src/FDM/SP/Balloon.cxx src/FDM/SP/BalloonSim.cpp
 	src/FDM/SP/BalloonSim.h src/Main/Makefile.am
 	src/Main/fg_init.cxx src/Main/main.cxx src/Time/Makefile.am
Removed Files:
 	src/Time/fg_timer.cxx src/Time/fg_timer.hxx