Clean up CUDA benchmarking code.
Makefile: update to CUDA 5.0 location at GB.
Add compile-time option for VEGAS shmem ids.
Added/Changed status memory and data buffer shared memory Id's to
match those of the vegas project. To enable the change, the compile
token USE_VEGAS_STATUSID must be set.
Added the USE_VEGAS_STATUSID token to the Makefile.
test_dedisp_thread: add null thread to clear results.
Reset CUDA error status appropriately.
test_dedisp_thread: Call correct net thread.