New TODO: Move & rename "serial_hsit_slave_tests.c"
Initial failing test for "master_connection"

Also add guard against trying to bind unasigned socket in
"server_socket.c"
"server_socket" now publishes interface for sockets

Move todo-list for "master_connection" to its test
Add function descriptions for "master_connection"
Rename 'readFromClient()' -> 'readFromMaster()'

This is in "master_connection"
There was a name collision in 'readFromClient()' from "server_socket",
now resolved
File renames

"ethernet_socket" -> "socket"
"server_socket.h/c" -> "system_socket.h/c"
'connectToMaster()' open socket