Remove 'DeprecationWarning: using a non-integer number instead of an integer will result in an error in the future' warnings
Remove a couple more 'using a non-integer number instead of an integer DeprecationWarning'
Make everything accept lists as input.
Merge pull request #3430 from amueller/test_list_input

[MRG] Test list input
Merge pull request #3433 from lesteve/remove-non-integer-deprecation-warnings

[MRG] Get rid of "DeprecationWarning: using a non-integer number instead of an integer" when running the tests
Added a parameter check on n_estimators in BaseEnsemble to raise error if it is not strictly positive.
ENH Make all decision functions have the same shape. Fixes SVC and GradientBoosting. Closes #1490.