Added loop factor demo
Got penalty_mex to compile
General cleanup

Signed-off-by: ScottHaileRobertson <heyemailthis+Git@gmail.com>
Fixed bug in trajectory (floating point rounding issue Mu He found)
Adding 2D itterative recon demo

Signed-off-by: ScottHaileRobertson <heyemailthis+Git@gmail.com>