ENH cleanup in check_pairwise_arrays, raise error on sparse input in chi2_kernel and manhattan_distance
COSMIT doc formating
train_test_split: test_size default is None
If test_size is None and train_size is not None, test_size
is the complement of train_size. If test_size and train_size
are None, test_size = 0.25.
Docstring is updated.
Existing tests didn't seem to cover much of existing behaviour
and no updates were added. New behaviour was tested.
Modified docstrings
Modified docstrings and tests
DOC updated whatsnew
FIX: makes our libsvm port compile under MSVC

Apparently, both clang and gcc support `and` instead of `&&` and
`or` instead of `&&`, but MSVC does not and raises a syntax error.
ENH added class_weight to Naive Bayes docs.
Merge branch 'master' of github.com:scikit-learn/scikit-learn
FIX random seed in FastICA testing.
DOC fix docstring of GMM
ENH Add "proximity" parameter to MDS.
FIX soime typos, modify test.
FIX another typo, fix examples
ENH updated to more examples.
ENH rename proximity to dissimilarity
COSMIT reorganized functions in the module
DOC : add doctring in plot_lasso_and_elasticnet.py
DOC: adding Bishop as ref for ARD
Merge pull request #1530 from agramfort/doc_lasso

Doc lasso + ARD