UMA_CHAT : Updated "UMA_CHAT" application.

Instead of handling signals asynchronously whith specific handlers,
handle them synchronously from the main thread. The main thread will
signal the neighbor manager thread by condition variables.
UMA_CHAT : Updated "UMA_CHAT" application.

The neighbor manager thread now sends and receives connection data. It
sends its own IP address, and as port number, by now the pid will be
used.