ENH all tests now pass with numpy 1.8.0rc1

Bottleneck now requires numpy 1.8.
WIP use new numpy nan functions...

test fail due to bugs in numpy
ENH nanargmin and nanargmax now match numpy 1.8.0
DOC tweak
REF remove local copies of scipy's nanstd, nanmean
REF remove local copies of scipy's nanstd, nanmean
DOC update benchmark results
REF tox now only tests numpy 1.8
BUG: Fix nanargmax/nanargmin for 1D integer arguments

These functions should return the argument of the *first* max/min value (like
numpy). This was not the case in the current release, since there is special
logic for 1D integer arrays (they are iterated through forwards instead of
backwards like all other array types).
DOC typo
Merge remote-tracking branch 'shoyer/fix-nanargmax' into np18

Conflicts:
	README.rst
	RELEASE.rst
Update C file
Merge branch 'np18'

Bottleneck now requires numpy 1.8