Merge branch 'karlrupp/feature-reduce-generator-usage'

karlrupp/feature-reduce-generator-usage:
  Removes BLAS level 1 and 2 operations from generator, only GEMM remains.
  Reasons: no support for char and short, some unnecessary kernel launches, poor CPU support.
  Fixes #167.

Conflicts:
	viennacl/device_specific/builtin_database/devices/gpu/nvidia/kepler/tesla_k20m.hpp