if TEdgeGoogleMapViewer is created at RunTime map is not initialized.

[littleearth]

• New WaitUntilInitialized procedure that can raise event OnViewerReady to prompt user to continue waiting. The default will cancel waiting as to stop application freeze.
• ShowMap will now check FInitComplete has been set and call InitMap if not. This is because Loaded is not called when TEdgeGoogleMapViewer is created at runtime.
• Demo application for RunTime creation