README Cleanup

@a1ronzo - here's my shot at readme cleanup for this repo.

I did add some content here by borrowing the last paragraph of the product description for a short blurb. I also dropped the line about the MPU-9150 which I found verbatim on that repo's README and assumed it was a copy/paste error.

Hardware license information is needed before this is ready. Please comment on what the license is or feel free to add the information directly on this branch. Thanks!