Use HKDEBUG to dump full requests and responses.

Replaces HKDUMPREQ.
Streamline the destroy command

Don't care whether the app has addons or dynos. I told you to destroy
it, so just f*cking destroy it :)
Change tail command to log.

Default to streaming output of all application log lines. Providing -n
limits the number of lines of output, and also prevents streaming.