ENH Addeded Fisher's method and Stouffer's Z-score method closes #3092
Refactor stats.combine_pvalues, add docs and tests

Refactored Fisher's method and Stouffer's method into a single method called
stats.combine_pvalues. Added documentation for this method, and added tests for
weighted Stouffer's method. Minor naming and style fixes.

Update THANKS.txt

Update autosummary

Use sf instead of 1 - cdf

Fix reST reference syntax

Coerce to ndarray, use more numpy functions

Add ref for test examples; test using python lists

Remove leftover text from git conflict

Add proper docstring format for list items
DOC: fix typos in zeros.py.
Merge pull request #3109 from cancan101/fisher_test

ENH Added Fisher's method and Stouffer's Z-score method
Merge pull request #4082 from cbrueffer/misc

DOC: fix typos in zeros.py.
MAINT: avoid redundant evaluation of user-provided function in l-bfgs-b optimization
TYPO: funciton
MAINT: default arg None->()
Fix typo in docstring for scipy.spatial.cKDTree
Merge pull request #4088 from abject/fixTypoDocstring

Fix typo in docstring for scipy.spatial.cKDTree
DOC: special: more clear instructions on how to evaluate polynomials
Merge pull request #4091 from pv/doc-polyval

DOC: special: more clear instructions on how to evaluate polynomials
Merge pull request #4083 from argriffing/streamline-approx-fprime

MAINT: avoid redundant evaluation of user-provided function in l-bfgs-b optimization