gtk: fix Application to be more robust when embedding mono
gtk: fix Application to be more robust when embedding mono

When embedding mono, Environment.GetCommandLineArgs() would not return
an array with any element.

Reported in the mailing list, by Vardar Sahin.

sillsdev/gtk-sharp,sillsdev/gtk-sharp,antoniusriha/gtk-sharp,sillsdev/gtk-sharp,openmedicus/gtk-sharp,Gankov/gtk-sharp,openmedicus/gtk-sharp,Gankov/gtk-sharp,orion75/gtk-sharp,openmedicus/gtk-sharp,openmedicus/gtk-sharp,sillsdev/gtk-sharp,antoniusriha/gtk-sharp,antoniusriha/gtk-sharp,Gankov/gtk-sharp,antoniusriha/gtk-sharp,Gankov/gtk-sharp,orion75/gtk-sharp,antoniusriha/gtk-sharp,orion75/gtk-sharp,openmedicus/gtk-sharp,Gankov/gtk-sharp,sillsdev/gtk-sharp,akrisiun/gtk-sharp,akrisiun/gtk-sharp,akrisiun/gtk-sharp,orion75/gtk-sharp,openmedicus/gtk-sharp,Gankov/gtk-sharp,openmedicus/gtk-sharp,akrisiun/gtk-sharp,akrisiun/gtk-sharp,orion75/gtk-sharp