* Added option "WITH_BF_CYCLES_CUDA_THREADED_COMPILE" for the people who have much RAM (8 or more) and can compile several kernels at the same time. If enabled, it uses the general BF_NUMJOBS flag.
* The option is off per default.
* Compile all of cycles with -ffast-math again
* Add scons compilation of cuda binaries, tested on mac/linux.
* Add UI option for supported/experimental features, to make it
more clear what is supported, opencl/subdivision is experimental.
* Remove cycles xml exporter, was just for testing.