show_app_log should also work when not using b/g deploy

[JohannesRudolph]

I totally missed #40 only implements live-tailing of application logs for b/g cf pushs. It would be really useful to have the same capability for "normal" cf pushs.

[lrstanley]

Any update to this? Only issue I see is that if the currentAppName isn't provided, it wouldn't know what the app name is that it should be checking the log for. Could we parse the manifest maybe? If there is a simple way to get the name, I can submit a PR.