add legally binding language to promissory note

This PR adds the legally binding language to the promissory note for borrower/lender to review. It improves the location of the sign/edit buttons for better IA.

notes/:id `notes#show`
![screen shot 2013-11-14 at 2 59 39 pm](https://f.cloud.github.com/assets/331004/1544439/65b5cd96-4d67-11e3-9f6a-ddfde5ff7cf2.png)