Added: Full UI for user to select read or write, locate directory and
file. Added so when reading a file from the server, user can only
navigate in the server directory for the file. ClientUI will be the
"main" client program, which will spawn threads of type client in order
to service the users demands. If the client UI is terminated, the client
thread will still finish what it is doing before ending, this way we can
ensure read and write operations will finish even if the client is
shutdown. A file called SingleRootFileSystemView.java has also been
added, for ensuring user can only select files from the designated
server folder when reading from the server.

TODO: Comment all code and implement Client to extend thread, and take
information from ClientUI to perform operations.
Merge branch 'master' of https://github.com/sysc-3303-1000000/TFTP
Added: Full UI for user to select read or write, locate directory and
file. Added so when reading a file from the server, user can only
navigate in the server directory for the file. ClientUI will be the
"main" client program, which will spawn threads of type client in order
to service the users demands. If the client UI is terminated, the client
thread will still finish what it is doing before ending, this way we can
ensure read and write operations will finish even if the client is
shutdown. A file called SingleRootFileSystemView.java has also been
added, for ensuring user can only select files from the designated
server folder when reading from the server.
    
TODO: Comment all code and implement Client to extend thread, and take
information from ClientUI to perform operations