~STABLE~ BACK FROM BUG - PLEASE READ

After a fatal bug that caused crashes whenever sending messages, rolled
back to this functionality:

- Buffers are now static strings
- Hello messages are disabled for debug reasons
- Messages are sent with the full header NXT | TRGT ; XOR {..} MSG
- The receiver anaylzes if message is echo,hello,or neither and only
decides wether to ignore or return the rx_str to java

!!! This version is stable !!!