Sanitized Error Messages, Removed Display Msg Bug

Added the WAVException class to aide in sanitizing error messages. Added
code to remove the spaces displayed before and after the message
displayed to the user if they are decrypting. Ex/ if message = "hello
world", it will display "hello world" and not "hello world
[etc]".
Added GUI changes and Fixed File Bug

Added scrolling feature to the message text area. Fixed a bug where the
program wouldn't close a file immediately after it was done with it.
Needed to force the Garbage Collector to run immediately. Added code for
sanitizing error messages.