Provide better source for lightblue (on OSX)

[gregjones]

For me at least, on OSX 10.7, the lightblue from the linked sourceforge page doesn't install. The fork here: https://github.com/pipt/lightblue-0.4 works fine

[Hexxeh]

I think Pebble are publishing a patched version somewhere?

[bmedicke]

They do have a fork at https://github.com/pebble/lightblue-0.4 but I have not tested that one. The fork from https://github.com/pipt/lightblue-0.4 worked fine for me (without changing the signature etc.).

[dlamblin]

The original doesn't support lion or mountain lion. The fork supposedly does but then all the python folks have to go out and get the full Xcode install just to build it. Someone who's built the library should just host the resulting binary somewhere.