VK1ET : Numerous changes to Port handling

Changes based on ideas from John VK1ET. His commit notes are as follows
:

1. Change input socket handling to avoid unnecessary memmove (use
pointers instead)

2. Add ability to read and decode binary beast format TCP.

3. Change output socket handling same as sbs_output - only call output
handler if there is a current client connected use separate ports for
beast in and out - no need for --net-beast flag. Will input/output
format defined by socket connected to. avr raw, beast binary and sbs can
be handled simultaneously.

4. Some comments changes, filtering of ModeAC to json,.