refactor: added comments, cleaned up code.

[adamgulde]

Addressed several issues with the codebase. See
issue #62 for some of the solved details.

• banker.py -- Most notably added a more robust unit testing
  manager. The user can create custom unit tests or
  choose from a list of pre-made tests, which are
  now detailed as they print to the screen.
  -- Moved battleship and tictactoe handling from
  handle_data() to their own respective functions.
  -- Added validate_name()
  -- Added comments, cleaned up code.
• modules.py -- Moved calculator module from player.py to
  modules.py. Streamlined a bit.
• monopoly.py -- Fixed printing bug where the player's name
  was not being printed as player.order instead of
  player.name.
• networking.py -- Added comments, cleaned up code.
• player_class.py -- Renamed class symbol from Player to
  MonopolyPlayer to clear up some ambiguity. This is
  reflected in cards.py, board.py, monopoly.py
• player.py -- Added inputting player name during
  initialization.
  -- Added bal function to get balance from banker.
  -- Moved calculator module to modules.py
  -- Added comments, cleaned up code.
• screenspace.py -- Removed print_board()
  -- Added whitelist to get_valid_int()
  -- Added comments, cleaned up code.
• Deleted testclient.py, testserver.py
• Updated .gitignore