ENH: improve performance of byte_bounds for continous arrays

reduces the memmap slicing performance issue in gh-3364 to only about a
4 times slowdown compared to 10 times.
BUG: fix non-swapping strided copies in GetStridedCopySwap

Fixed PyArray_GetStridedCopySwap{Pair,}Fn returns paths that do not swap
the data.
It never triggered because the alignment requirement for complex data
was too low (4-8 bytes) and always fullfiled by the memory allocator.
As this is now fixed it caused failures on sparc with 16 byte long
doubles.
BUG: fix small leak in datetime metadata initialization
BUG: set filename to None for memmaps of unnamed files

Closes gh-3302
BUG: fix undefined function and add integer divisions in numarray
BUG: fix a spelling error in mtrand.beta docstring
BUG: add platform specific python include directories to search paths

the generic and platform specific path diverge in python3.3 in ubuntu 13.04
BUG: hardcode some known shared library extensions

the configuration variables are not a reliable mean to get the shared
library extension. darwin, windows and debug linux are wrong in these
variables.
SHLIB_SUFFIX is also wrong as of python 3.3.1
closes #3057
Merge pull request #3463 from juliantaylor/1.7.x-bugfixes

1.7.x bugfixes