ENH: allow MulticlassClassifier to operate without combiner thus just spitting out all pair-wise predictions (without any voting)

work here is to superseed even more ad-hoc and fragile approach now
found under mvpa2/sandbox/multiclass
RF: Removing what was apparently copied/fixed in sandbox/multiclass.py
RF: no "combiner" -- no "estimates" in CombinedClassifier (and no warning)
RF: squeeze out the degenerate dimensions for pos/neg labels in pair-wise classifiers
RF: place labels for pair-wise results into a single fa matching original attribute (e.g. "targets") in tuples

our sensitivity analyzers already do the same
Tuples allow to have varying number of labels for each member, e.g.
if it was 1-vs-all
PY3+RF: fix issue in python3 not picked up by 2to3. Addresses https://github.com/PyMVPA/PyMVPA/issues/130
???: embedded comments into volume_mask_dict for TODO (+ minor code changes and DOC changes)
ENH: maintain GLM wrapper + enhance set of reported statistics with zstat

Added zstat at the end of the 'list' to maintain compatibility
ENH: remove "shape" as explicit argument in FlattenMapper.__init__
Merge branch 'master' of https://github.com/PyMVPA/PyMVPA
DOC: Fix minor spelling/grammer in tutorials 0-2

Mostly minor spelling or grammer fixes, with a few sentence rewrites to
hopefully improve clarity.  Also updated a few outdated links
DOC: Fix minor spelling/grammer in tutorials 3-6
NF: test for queryengine i/o
Merge branch 'enh/surfing' into _tent/surfing
BK+API: rename "aux_get" to "get_aux"
DOC: more documentation and some answers to issues raised by Yarik
BF: return proper meta data even when set to False or None
BF: return proper meta data even when set to False or None
DOC: explain why use of "merge" instead of "update"
RF: use get_aux instead of deprecated aux_get