Minor fixes, help function, rename

Move all help printing into dedicated function to not clutter up the
main shell function. Rename ctrl_shell function to just shell.
Add exfiltration capabilities

Can now use the `exfil' command to pull back files from target onto
server.
Rename to poet
Further partition output directory

Segregate archived files based on the command they were produced by
(exec, recon, exfil)
Fix exec bug

If one of the commands in the exec list contained ' -o ' in it, it would
confuse the exec parser. Update the regex to mandate that the -o
parameter must be right after 'exec'.
Minor fixes
Add self destruct

Client script deletes itself
Add download and execute feature