tree: add min_weight_fraction_leaf
forest: add min_weight_fraction_leaf
min_weight_fraction_leaf and min_samples_leaf: test both best-first and depth-first tree building
gbrt: min_weight_fraction_leaf value test
tree: use min_weight_leaf internally while exposing min_weight_fraction_leaf
utils.testing: add assert_greater_equal and assert_less_equal
forest: test min_samples_leaf and min_weight_fraction_leaf
min_weight_fraction: comments and pep8
test assert_greater_equal and assert_less_equal
min_weight_fraction_leaf: narrative docs
min_weight_fraction_leaf: narrative doc update
Update what's new
MAINT skip tests that require large datadownload under travis
fix typo (on -> one)
Merge pull request #3334 from ami-GS/external

fix typo (on -> one)
MAINT add docstring to explain the motivation of the fixture
Merge pull request #3333 from ogrisel/maint-skip-download-tests

[MRG+2] MAINT skip tests that require large data download under travis
Typo
MAINT Include binary_tree.pxi in source distribution

Fixes #3331.
ENH Add partial_fit to GaussianNB

Uses Chan/Golub/LeVeque update for model parameters. Does not implement
sample weighting.