Make the OpenWRT config more standard

[parkrrrr]

Right now we start with a modified branch of OpenWRT, then copy some files into that.

1. Figure out what needs to be done to make the branch of OpenWRT suitable for a PR to the OpenWRT project. This might mean moving some config values around.
2. Figure out how to use e.g. make diffconfig to do what needs to be done with the config.
3. Move the buildme script out.
4. Move all of the copying-to-OpenWRT stuff to a makefile somewhere.