Improved GPU utilization by separate queuing GPU tasks and synchronization. 1 CPU can now drive 8 GPUs fully

Improved cuda code after profiling with nvvp
1) Improved occupancy of addnoise_do by increasing block size to 256
2) Improved occupancy of cuztilt_do by increasing block size to 32x32
Improved gpu_prop_grid_do by utilizing shared memory to hold certain variables. Reduced register usage and eliminated
spilling to local memory. Increased occupancy in the mean time.
Improved a few other kernels after nvvp reveals low occupancy.
Fixed misc compiling issues.
Improved GPU distribution of tasks. Timing is now reduced to 0.023 ms.
cleanup configure.ac