Add fit_transform to FastICA.
Add inverse_transform to FastICA.
Add docstrings to methods in FastICA.
Address @dengemann's comments.
Add test.
Push failing test.
FIX transform tests
FIX: remove inplace mod
ENH fit_inverse_transform for FastICA

Modeled after KernelPCA's parameter of the same name.

Conflicts:
	sklearn/decomposition/fastica_.py
DOC document mixing_ attr on FastICA
COSMIT attribute checking in FastICA
COSMITS
FIX: inverse transform + add mean_
COSMITS
FIX: syntax typo
FIX: tutorial
COSMITS + DOC
COSMITS
ENH: improve tutorial to be more clean.
ENH + FIX: remove inverse-t kwarg + fix mean_