Fix for the last two URLs in Readme.md

[mcanthony]

The following links found at the base of Readme.md:

Head over to [http://braid.nexusosc.com](braid.nexusosc.com) and contribute an instrument.
Built on the NexusUI interface platform: http://www.nexusosc.com

Inevitably point to https://github.com/lsu-emdm/braid/blob/master/braid.nexusosc.com and https://github.com/lsu-emdm/braid/blob/master/nexusosc.com; yielding a 404 error on Github. I think this is caused by the absence of "http://" in front of the url specified in (url), causing at least my browser (chrome) to treat it as a sub of the current uri.

This portion (for your copy-paste convenience) should read:

Head over to http://braid.nexusosc.com and contribute an instrument.

Built on the NexusUI interface platform: http://www.nexusosc.com

(sorry about the confusing linkification, this is the closest I could get to somehow disabling githubs md processing)