Add privately parameter to send_message and send_command
Add privately parameter to send_message and send_command

This adds the ability to send private messages and commands within a
handler's test suite.

MatthewKrey/lita,litaio/lita,litaio/lita,tristaneuan/lita,jimmycuadra/lita,liamdawson/lita,tristaneuan/lita,liamdawson/lita,crimsonknave/lita,crimsonknave/lita,jimmycuadra/lita,brodock/lita,brodock/lita,MatthewKrey/lita