DOC: clarify docstring of rolling/expanding moments

- document center argument
- add note about the result set at right edge by default
- clarified freq keyword a little bit
DOC: fix doc build warnings
CLN: Change assert_(a [not] in b) to specialized forms

Work on #6175. Changes instances of assert_(a [not] in b) to specialized assert[Not]In(a, b).
ENH: pd.infer_freq() will accept a Series as input
API: pd.infer_freq() will now raise a TypeError if given an invalid Series/Index type (GH6407)
Merge pull request #6408 from jreback/freq_ops

API: pd.infer_freq interacts correctly with a Series
API: validate conversions of datetimeindex with tz, and fixup to_series() to handle (GH6032)
Merge pull request #6398 from jreback/index_coerce

API: validate conversions of datetimeindex with tz, and fixup to_series() to handle (GH6032)
DOC: use ipython in bool replace doc warning
DOC: use code block for shorter error message
Merge pull request #6412 from cpcloud/replace-bool-doc-fix

DOC: use ipython in bool replace doc warning
TST: GH6410 / numpy 4328
Merge pull request #6413 from jreback/32_bit_tests

TST: GH6410 / numpy 4328
BLD: add optional numpy_dev build
Merge pull request #6414 from jreback/numpy_dev

BLD: add optional numpy_dev build
BLD: tweak numpy_dev build
Merge pull request #6362 from jorisvandenbossche/doc-rolling

DOC: clarify docstring of rolling/expanding moments
BUG: inconcistency in contained values of a Series created from a DatetimeIndex with a tz, related (GH6032)
ENH #6416: performance improvements on write - tradoff higher memory use for faster writes.
ENH: backport Python 3.3 ChainMap

ChainMap implements a list of mappings that effectively functions as a single
dictionary. This class is very useful for implementing scope. This commit also
adds a DeepChainMap subclass of ChainMap for writing and deleting keys.
CLN/ENH: use Scope.swapkey() to update names

Also useful for replacing local variable names with their mangled versions.