Icaos are collected when sceneries are loaded to layergroup class
check icaos to layergroup added

Helps to get double definitions of airports in one layer.
First simple gui layout in tkinter
font definition added
scrollbar for layers
Details added
variable for the row definition in the grid
minor changes
Merge branch 'gui-development' of https://github.com/lyckade/xpstart into gui-development
actionsButton added
threading added
First useable gui version
xpstart_gui modified for release
Gui works now for first release
Files renamed, debug output deactivated
Merge pull request #11 from lyckade/gui-development

Gui development