Rename console as conn

Kinda-sorta reflects the intent better which is to have a connection to which
sql may be piped.
Format outputs for a stream by default if stdin is not a tty

Plays well with pipelines.
Ensure -c works correctly in dbu-conn
Add -H to print headers in results
Add -p to mysql output in preview mode

Without this the command cannot be successfully copy-pasted; you end up getting
a connection error rather than a password prompt.