Openbazaar python launcher

new pull request after 1st round of reviews.
Thanks @Renelvon this has the merged changes from your repo.

(@Renelvon I kept that REVERT commit you put there as I'm not sure I understood what was right or wrong about it, I figured it'd be easier to fix here now)
I actually like it the way it is, since the method is used on a parent process which does need to exist, otherwise the program hijacks the command line until it ends. Think of the call to `node_starter` in its own process, as the process fork bash does with the old `run.sh` when it invokes `python node\openbazaar.py&` (with that `&` at the end)

I could move this logic to `openbazaar.py`, but it'd still have to be in a method so that it can be invoked as the target of the process using it, and then if I moved it there I'd also have to move the `start_node` method, which would probably cause even more refactors, so I think it's just better to leave this as is.