DOC: Add mention of PyArray_SetBaseObject stealing a reference
Merge pull request #3130 from mwiebe/setbaseobj_doc

DOC: Add mention of PyArray_SetBaseObject stealing a reference
Get pypy to install numpy

tested with pypy-1.9,
requires getting rid of pypy's obnoxious builtin numpy first.
Disable detecting imports from within the source tree.

Reason: we broke the install-time mechanism behing it.
Hack numerictypes so that it imports
Make numpy importable in PyPy.
Make arrays printable