Moving getopts.m into a separate submodule

Squashed commit of the following:

commit 967c9e355eb244c2d03184170a0f317bcbdafbbf
Author: Zhengyun Zhang <zhengyun@smart.mit.edu>
Date:   Tue Dec 2 12:13:26 2014 +0800

    oops, can't have +folders inside private for MATLAB

commit 34a3435892b9585867cc1ee3879167c33d8c51f7
Author: Zhengyun Zhang <zhengyun@smart.mit.edu>
Date:   Tue Dec 2 12:04:42 2014 +0800

    splitting off +mhelpers