ENH: use lgamma function from John D. Cook

Conflicts:
	sklearn/metrics/cluster/expected_mutual_info_fast.c
	sklearn/utils/lgamma.cpp
	sklearn/utils/lgamma.pyx
	sklearn/utils/setup.py
Merge branch 'master' into lgamma_port

Conflicts:
	sklearn/metrics/cluster/expected_mutual_info_fast.pyx
ENH we require a version of sphinx sufficient for "new" numpy_ext to work
FIX instead of appending numpy_doc to the list of extensions, directly add when creating the list
BUG don't write comments in SVMlight dumper by default

Fixes part of Issue #1501
DOC some sphinx fixes
DOC fix in mds example (new interface)
DOC mds example: suppress warning for explicit initialization
DOC don't use deprecated parameter rho in the lasso / enet examples
COSMIT typos in hierarchical clustering warning
DOC more sphinx fixes
BUG hotfix for issue #1501: sort indices in SVMlight i/o

CSR matrices are strange beasts.
EXAMPLE don't use deprecated interface in lasso model selection
COSMIT pep8 in examples
COSMIT pep8
DOC more sphinx fixes
FIX sort indices in CSR matrix for SVM
DOC fix travis URLs in README

https://secure.travis-ci.org/scikit-learn/scikit-learn incorrectly
redirects to https://travis-ci.org//scikit-learn/scikit-learn, which
doesn't work.
TST sorting CSR matrix indices in SVMlight file handling
dpgmm: setting the weights to something reasonable