removes two wrong const from member functions
adds defaulted copy assignment and move assignment operator to basic engine
adds missing semicolon in basic engine
adds pointer to engine object to basic system so that other systems can be accessed
adds engine example to main
removes noexcept from defaulted copy constructor and move/copy assignment operators. fixes compilation error caused by wrong functon name
change run member function in basic engine to pure virtual
add window class which inits sdl and glew and displays a window
add window and game loop to basic engine
add logger to basic engine
add log output to window
add colored log output and log file flush on logger construction