MAINT: check versions of dependenecies
BUG: fix sklearn version requirement
ENH: add a warning on empty mask
BUG: mask interpolation should be nearest
TST: more tests
MAINT: remove leftover file
Cosmit: move code around
MISC: refactor to remove code duplication
ENH: masking strategy for homogeneous background
ENH: better error message
ENH: integrate background mask heuristic
Integrate better new masking strategy
ENH: add slight smoothing to EPI mask extraction
BF: closes issue #162
ENH: cosmetic changes to testcase
BF: broken testcase
Merge pull request #163 from dohmatob/fix-issue-162

BF: closes issue #162
Merge pull request #161 from GaelVaroquaux/background_mask

New masking strategy: Background mask
COSMIT: naming and simplification in test_masking
MISC: useful comment