DOC: Update PyArray_SearchSorted docs in c-api.array.rst
DOC: document NPY_BEGIN_THREADS_THRESHOLDED
ENH: Cast non-object arrays to float in np.poly

Closes #5096. Casts integer arrays to np.double, to prevent
integer overflow. Object arrays are left unchanged, to allow
use of arbitrary precision objects.
DOC/MAINT: Python 2.6 or 3.2 required

Installation docs still stated Python 2.4 is supported, while not mentioning
3.x at all. Also corrected the statement that distutils is in python-dev on
Debian, while it's actually in the main package.

Several parts of the dev docs and some comments also referenced now-irrelevant
2.5 bugs/limitations.
ENH: add small kernel correlate function

For cases like convolve/correlate with small kernel calling out to BLAS
dot is very slow as it goes through many wrappers and BLAS is typically
optimized for very large data.
So add a template utility file and add a special function for small dot
products.
2-4 times faster than openblas dot for kernel sizes < 11.
ENH: logaddexp handling of same sign infs without warnings
TST: logaddexp and logaddexp2 with infs should issue no warnings
ENH: better handling of NaNs in logaddexp
ENH: add subok flag to stride_tricks (and thus broadcast_arrays)
Convert as_strided input to array first
BUG: financial.py pmt() method rate==0 will cause warning. Caused by misuse of where() and division by 0. Fixed by calculate with different method depending on rate == 0.0 or not. Also, added the feature for asscalar() to take in scalar. Fixed by adding turn any parameter into array first.