GUIelement.cpp: GUIelement.h function definitions moved to cpp
SGengine.cpp: SGengine.h function definitions moved to cpp. Initwindow method implemented. SGengine construtor implemented.
SGengine.h: Basic fields/functions defined
Button.h Basic functions/field defined.
SGengine.cpp: Constructor fixed
SimpleGUI.cpp: .h functions will be defined here
SimpleGUI.h: init function removed. InitWindow function added. LoadfromXML function declared