ENH: make use of just added prereq= for Benchmarks to skip verification of numpy.copyto benchmarks when it is N/A
progress numpy just for fun
ENH: adjusted import_numpy with manual pruning of all numpy. modules within sys.modules
ENH: actually even with manual pruning it seems to be not fully representative -- thus removing

manual python -c 'import time; t0=time.time(); import numpy; print time.time() - t0'
never gives less than 120ms while the Benchmark gives around 86ms.  While we do not know what exactly contributes
there better to exclude altogether