DOC: additional notes about FFTs, typo fixes, etc.
MAINT: Use boolean defaults for boolean parameter overwrite_x
MAINT: Use boolean defaults for boolean overwrite_x parameter
DOC: Add simple ifft Returns section
DOC: Add examples for DCT, minor changes to DCT docstrings
DOC: elaborate on rfft and dct efficiencies
BUG: special/specfun: fix argument value check in KLVNZO

documentation of KLVNZO(NT,KD,ZO) in scipy/special/specfun.f
says 1<=KD<=8. Previous code resulted in always True.
scipy.signal.wavelets.cwt doc easyfix from #2748 ticket
Merge pull request #2780 from aleufroy/fix-2718

BUG: special/specfun: fix argument value check in KLVNZO
MAINT: remove leftover check for Python <= 2.5.  Some cleanups of comments.
Merge pull request #2775 from endolith/patch-3

DOC: fftpack: add more notes about FFTs, real FFTs, fix typos, change boolean defaults to False
Merge pull request #2784 from duskglow/doc-cwt

DOC: scipy.signal.wavelets.cwt argument order fix 

Fixes gh-2748
Merge pull request #2783 from rgommers/cleanup

MAINT: remove leftover check for Python <= 2.5.  Some cleanups of comments