Add set varname=value MCC command

- Allow to use vars declared in scripts or directly by the user
- Commands my now use %variable% as well
- Moved "help" command from RemoteControl to inner MCC command manager
- The only special command is "wait", which is only available in scripts
Todo: Solve ambiguity between MCC help and Server help commands
Note: Auto accept tpa suggested by MousePak
Note: Manually choosing MC version suggested by ZizzyDizzyMC