DOC: minor tune ups to corrcoef and WinnerMeasure docs
BF: CorrStability -- fix scaling and operation on arbitrary sa

This is old code which might get deprecated sooner than later. Was not tested
at all
RF: use 'space' instead of 'attr' for consistency with Anova etc
ENH: just minor tune ups to make code a bit more generalizable and concise
Merge pull request #218 from yarikoptic/bf/corrstability

Bf/corrstability: rudimentary fixes and tests for CorrStability found in the codebase