Udp dev

[glennkreisel]

the read(buf, len) was broken, not limiting bytes read and not even returning the proper unread bytes from the sock buffers.
Also the AvailTcpData was not calculating the proper unread bytes in the buffers.

Please look over this and compile.
Let me know if you have any questions.
How can I setup the build environment for this to flash the firmware?

@mlafauci ping

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