Begin adding session support

- session.cpp/h for the Session and SessionData classes
- added session management to Server
- session objects own the socket handler once given it
- renaming of some fields/methods for readability
Additional infrastructure for login sessions and general code cleanup
Reorganized directory layout

- gitignore will no longer ignore project file
    needed so that switching branches doesnt cause file-missing issues
- all development files moved inside ./dev directory
    includes src folder, project files, intermediary obj files, etc
- root folder should be limited to non development directories/files
Cleaning references to files removed in previous commit
Finished requirements for basic echo

end of line client settings recognized and handled
sessions now able to recognize zero length commands
server will echo all received text back to ONLY the originator