FIX raise error when number of features changes in partial fit, Add common test for inconsisten number of features for partial fit.
Fixed issue 3815. Discrete AdaBoostClassifier now fails early if the base classifier if worse than random.
FIX #2986: ZeroDivisionError in LinearRegression on sparse data
DOC: add funding from Paris-Saclay Centre for Data Science

Also:
* Completed INRIA funding description
* Fixed Google Summer Of Code rst link
DOC FIX: typo and minor update
Merge pull request #3854 from justmarkham/doc-changes

DOC FIX: typo and minor update
Merge pull request #3833 from amueller/sgd_partial_fit_variable_length

[MRG] TST raise error when number of features changes in partial fit
Merge pull request #3853 from ogrisel/backport-lsqr-fix

[MRG] Fix ZeroDivisionError in LinearRegression on sparse data
Added missing GSOC student
TST stronger non-regression test for #3815

Also fixed the testing imports.
Merge branch 'pr/3837'

Fixes gh-3815.
FIX make assert_raises_regex backport for 2.6 consistent with 2.7+

Use regex.search instead of regex.match.

Furthermore, silence the deprecation warning from Python 3.4 as
assert_raises_regexp is now deprecated in favor of the shorter name:
assert_raises_regex.
Merge pull request #3861 from ogrisel/fix-python-2.6-test

[MRG] FIX make assert_raises_regex backport for 2.6 consistent with 2.7+
ENH use specific warning class for RP
Raise error when sparse matrix is supplied to predict in KNeighborsClassifier.
gen_rst informs file with missing documentation
fix tab error
Merge pull request #3862 from Titan-C/doc_comment

gen_rst informs file with missing documentation
Merge pull request #3852 from lesteve/add-cds-funding

[MRG+1] DOC: add funding from Paris-Saclay Centre for Data Science to the website
Merge pull request #3860 from ogrisel/custom-rp-warning

[MRG] ENH use specific warning class for RP