Show op_return in tx dialogue

Very basic as of now... needs more polish. But I am open to more suggestions as to how to sanitize etc.

It seems as though these two places are the only three places necessary to show op_returns.

Please let me know if you have any other info / suggestions.

P.S.: If you load `d29c9c0e8e4d2a9790922af73f0b8d51f0bd4bb19940d9cf910ead8fbe85bc9b` "From the blockchain" with this commit, you will not be disappointed.
Hint: here's a screen cap. (I made the text box larger to accommodate.)
http://i.imgur.com/QOKyRO1.png