ENH: add failing test exposing bug in RandomizedPCA
FIX: only center if copy == True
ENH: get it right.
FIX: inverse_transform; tests
DOC better doc message
API: get rid of **params in PCA estimators.
DOC: more doc string fixes in pca.py
DOC: more fixes in pca.py doc strings
STY: get rid of unnecessary identifiers
FIX: X.copy() test now works
STY: removing unnecessay import
COSMITS