DEP: put back veccdf/vecfunc/vec_generic_momemt in stats.distributions.

Removed erroneously in gh-3243 for 0.14.0.  These methods were always
private ones but not marked as such, and as the comments on gh-3243 show
they were used. Hence now deprecated.
ENH: cluster: reimplement the update-step of K-means in Cython
MAINT: cluster: remove the conditional import for _vq
BUG: special: ellip(k,e)inc nan and double expected value

Both ellipkinc and ellipeinc returned nan for a particular value
due to cancelation in a tangent update formula.  Double the
expected value was returned in a small region around the value
returning nan due to using a fragile argument reduction formula.

Fixes gh-3550
Merge pull request #3704 from ewmoore/ellik_fix

BUG: special: ellip(k,e)inc nan and double expected value
BUG: stub out spurious methods of Akima1DIntgerpolator

from_spline and from_bernstein_basis are inherited
from PPoly, and neither produces an Akima interpolator.
DOC: add See Also sections to Pchip and Akima interpolators
Enable automated testing with Python 3.4
Merge pull request #3750 from frewsxcv/patch-1

Enable automated testing with Python 3.4
ENH: add multivariate normal option to return the effective rank
MAINT: remove return_rank optional argument, add .rank multivariate_normal_frozen attribute, add tests
MAINT: learn how to use frozen distributions
MAINT: aggregate covariance matrix info into an object
MAINT: do not silently reduce dimensionality, but allow reduction with a forcing flag
TST: more tests for singular covariance matrices
DOC: one eigh -> one call to eigh
DOC: add the allow_singular flag to more parts of the docs
MAINT: add mvn error checking
MAINT: typos
DOC: move __init__ docstring into the class docstring