Kergoth bb det layers

Pull in changes from ATP 2013.10 by kergoth.

<kergoth> fyi, altered the setup scripts so the layer requirements match the readme. now meta-mentor can be used with just oe-core and meta-yocto, but all our stuff will be pulled in if available, which of course it is for mel
<kergoth> that way any open source folk cloning the layer don't need to go grab meta-networking and crap
<kergoth> this was jsut a small step in the right direction, correcting behavior for upstream, and also fixing bugs in layer dependenecy handling
<kergoth> previously, having an optional layer with deps would result in not including that layer if its deps weren't already configured/included, rather than including them if they're available