v3.0 Added subprocess

Tmux not required now if you're not using RCON. Can now start Minecraft server as subprocess with Popen(), uses stdin.write() to send commands to the server, and reads latest.log file for output. I might work out the code to read the output directly with stdout, but for now it's easier to use the log.
run_bot.py, run argument can't start the server, you have to start the server with ?start Discord command.
New use_subprocess boolean added. You can run the bot in Tmux and still run the server as a subprocess, just set use_tmux and use_subprocess both to True.
I have a feeling there's gonna be plenty of bugs to find, please be patient.