This is safe because the signals are handled back to back inside the emit function. Therefore, it can be freed directly after emission. This solves the problem of the status message not being freed if no handler is connected to the signal.
* Remove Command line and GUI rendering code
* Add LayerSettings Class with all options
* Prepare to remove mapping parser. Is now integrated in LayerSettings
* Adopt all renderers to check if the supplied layer_info struct has to be rendered.
Further todos:
* Implement correct command line parsing.
* Implement Layerselector and GUI to use new LayerSettings class
