Updated the train method to be an InputArrayOfArrays, so the Python wrapper now generates the correct code (and it works).

Updated the documentation to (1) reflect the latest changes and (2) answer some questions I were asked.

Fixed facerec_eigenfaces.cpp demo sample: it contained hardcoded values, which made wrong element access possible. Fixed unsigned integer/signed integer warnings in facerec.cpp.

Bug #2214: Fixed bug, when calling the train method multiple times. The Eigenfaces and Fisherfaces method now re-estimate the model, the LBPH method appends the new data to the existing model.

Optimization introduced in b782d8bb only works for 64-bit builds, but
ifdef failed to check for this.

ASIFT

ASIFT

If no Kinects are present, crash can result from
stepping beyond end of device list. Now we check
to ensure this does not happen.