Lab in "master_connection.c"

"master_connection.c" is now the main function. I use it to laborate
with sockets. Currently "master_connection.c" awaits a connection on
port 3071, waits for 10s then polls the socket file descriptor for
readable data. If any message is found it is output.

Simple client-server example
http://www.linuxhowtos.org/C_C++/socket.htm

How to accept sockets with finite timeout
http://stackoverflow.com/questions/14045064/how-to-accept-socket-with-timeout

For non-blocking socket read
http://www.tenouk.com/Module40c.html
Clean up left-over comments and blank lines
Restore "master_connection.c"

Started working out the socket interface. Intended system wrapper
functions are now static functions of "server_socket.c"

Aiming for
* Wrappers for system calls that manage sockets
* Testable error management for failed system calls
* Testable read-buffer management
Refactor: Extract read and write to client

Read and write operations towards the client are now functions of
their own
Refactor: Extract 'closeSockets()'
Clean up comments

Remove left-over comments
Refactor: Rename 'rfds' -> 'fileDescriptorSet'
Move "server_socket.h/c" to "system" directory

Remove "ethernet_socket.h/c" because they are empty and I will likely
distinguish the server socket operations from the client socket
operations, using different files
Add "planned functionality" comment

Add "planned functionality" list for "master_connection.c"
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
Remove unused file inclusions
Function description correction

"Client" -> "Master"
Uniform filenames in "system" directory

Prefix all system wrappers with "system" to distinguish from wrapped
system headers - This was an issue for "socket.h"