Squashed 'lbfgsb-matlab/' content from commit 9e65d63

git-subtree-dir: lbfgsb-matlab
git-subtree-split: 9e65d63dcc4cc616f41b92f13d4008643d334ab3
Merge commit '3e580aaafeddf625cfe0ec683bdd44dc03a817df' as 'lbfgsb-matlab'
random sampling with unconstrained L1 and L2 solutions as priors