Added qp_admm and proj_simplex (utility for qp_admm)
Using threshFull_mixed (the closed form proximal operator)
Initialized RHO to 0.1 for each call to mlr/rmlr ADMM (used to be static)
Increased default ADMM_STEPS to 20 (to compensate for static RHO)
Merge https://github.com/khdlim/mlr

Conflicts:
	rmlr_demo.m
merge https://github.com/khdlim/mlr/commit/80cbe49910faf1d95696ec44bb0831ba2b858ef1