DOC add missing datasets helper
ENH remove deprecated
fix whitespace around new tree.pyx docstring
Missing value imputation
TEST: cosmit on err_msg
Raise an exception if rows are full of missing values
FIX: doctest
Better error message
Fix tests
Fix tests + doc improvements + renaming
Add test with default value of copy + doc improvements
Imp readability
Fix use of as_float_array
pep8
Imp variables names
Del use of as_float_array + naming and documentation improvements
Fix use of mask
Fix import names
ENH remove deprecated things (2)
Update what's thanks @NicolasTr