whitespace only fixes to numpy.lowlevel

Fix indentation and trailing whitespace
make OpenCL benchmark run in absence of OpenCL

This may seem a strange thing to do but the numpy-only benchmarks are
still useful. The speedup numbers, however, are meaningless.
remove ipython directive from Sphinx docs

The IPython directive appears broken with IPython 2.0. Since it was only
used in one place, work around it.
Merge branch 'remove-ipython' into pypy-support