option to choose between owner/active permission when generating unsigned transactions

[haggbart]

Currently you have to edit the json unsigned files manually.

[aaroncox]

There may still be some merit in allowing a change on the Download/Copy stage of creating the unsigned transaction, but I'm debating on whether we still need to make this change at this point.

With the 0.6.x release branch, you can create watch wallet profiles for both the owner and active permissions, and then swap between them based on which authority you'd like to sign with.