Replaced Eigen by more recent version.
Extended MCGSM by means and linear features.
Eigen assertions now have to be disabled explicitly using EIGEN_NO_DEBUG instead of NDEBUG.
Merge branch 'develop' into means
Fixed gradient.
Implemented pickling of means and linear features.
Merge branch 'develop' into means
Made unpickling backwards-compatible.
Fixed bug in conditional sampling of labels with preconditioner.
Merge branch 'develop' into means
Merge branch 'means' into develop

Conflicts:
	Makefile
	code/cmt/src/mcgsm.cpp