better error reporting and is not a speed bottleneck.

non-square matrix.

some landmarks are missing.

out by Yan Xu.  One of the face locations was mistakenly used twice while
another was skipped.  This change breaks backwards compatibility with the
previous feature extraction output but should slightly improve accuracy of
classifiers trained using these features.

switching to projected gradient steps.

Revise help message

and try to link against that one rather than whatever might be installed
system wide.

installed already.