F54: Separate window's functions on standard and window-specific. (Finished)

Done - F54.1: Separate drawing function.
Done - F54.2: Separate left click processing function.
Done - F54.3: Separate right click processing function.
Done - F54.4: Separate double click processing function.
Done - F54.5: Separate key processing function.
Done - F54.6: Separate char processing function.
Done - F54.7: Separate rednet processing function.
Done - F54.8: Separate rupdating function.