Added knife vault edit
Added knife vault show to eventually replace knife vault decrypt
Changed all banner lines to say (options) instead of listing options
Added edit to vault_create when content isn't specified on the command line
Added edit and show to README, removed decrypt
Fixed typo in error message
Reformatted KNIFE_EXAMPLES.md, renamed decrypt -> show, added edit, re-ordered things
Fixed docs on how to run tests
Forgot to use vault_mode instead of mode in vault_show and vault_edit
Added deprecation warning to knife vault decrypt
Merge pull request #72 from eklein/addl-knife-cmds

Rebased PR on top of jgeiger's merged PR
Missed replacing "decrypt" w/ "show" in README.md
Merge pull request #73 from eklein/patch-1

Missed replacing "decrypt" w/ "show" in README.md