DBCSR: name threads in cuda nvtx.
DBCSR: Make multrec-limit an input keyword
DBCSR: Remove unnecessary calles to cudaGetLastError
DBCSR: Changed color hash for cuda nvtx ranges
DBCSR: rename keyword n_stack_buffers to cuda/n_buffers
DBCSR: Add smart default value for comm_thread_load
DBCSR: Make clearing of product_wm lazy
DBCSR: Add mempool for cannon working matrices (conserves size-guess for next multiplication)
DBCSR: Tune size_guess, move GPU-transfer up (Joost)
Added null pointer checks to dbcsr_cuda_streams