New File Content System

Added: There's finally a "good" solution for the file content problem. Classes which want to get used as file content have to implement FileContent (such as Program or the new class StringContent). Furthemore, we no longer store other objects like environments in files directly.
Small Argument Order Cleanup

Fixed: The argument order in several shell programs is now more logical.
Renamed DeleteFile & MakeFile

Added: DELFILE and MKFILE are now called FDEL & FMK.
File Content Shell Utility

Added: FC can read and write text file content (or single lines).
DesktopState will be able to house other widgets

Added: Made some changes so desktop state will be able to handle other widgets than a desktop one.