Reworked command line processing for the GUI slic3r. Now the config is loaded first, then the model files (also the configs from AMF/3MF are applied), and lastly the free standing parameters are applied.
Fixed unescaping for command line parameters. The string parameters are now not unescaped, string vector parameters are unescaped only if enquoted.
Tab::load_current_preset() - disabled CallAfter for predictability. With CallAfter, it was difficult to call the method in sequence with other methods.
Fixed some missing ->Destroy() calls on dialogs created from MainFrame
Fixed some compiler warnings.