Improve "Snap Object to Floor" functionality
Improve "Snap Object to Floor" functionality

- Display an error message if no selected nodes could be snapped
- Only register an undo/redo action if at least one node
  could be snapped
- Increase the maximum snapping height to 20
- Increase the negative snapping limit to 0.2

guilhermefelipecgs/godot,Zylann/godot,vkbsb/godot,honix/godot,BastiaanOlij/godot,vkbsb/godot,godotengine/godot,Valentactive/godot,vnen/godot,sanikoyes/godot,godotengine/godot,Faless/godot,honix/godot,MarianoGnu/godot,ex/godot,firefly2442/godot,firefly2442/godot,Shockblast/godot,Shockblast/godot,ex/godot,ex/godot,Valentactive/godot,vnen/godot,vnen/godot,sanikoyes/godot,Shockblast/godot,Paulloz/godot,godotengine/godot,honix/godot,guilhermefelipecgs/godot,guilhermefelipecgs/godot,DmitriySalnikov/godot,godotengine/godot,ZuBsPaCe/godot,akien-mga/godot,vkbsb/godot,Faless/godot,firefly2442/godot,josempans/godot,Valentactive/godot,godotengine/godot,MarianoGnu/godot,Zylann/godot,ex/godot,Shockblast/godot,MarianoGnu/godot,ZuBsPaCe/godot,vnen/godot,pkowal1982/godot,BastiaanOlij/godot,ZuBsPaCe/godot,pkowal1982/godot,Paulloz/godot,vnen/godot,Faless/godot,sanikoyes/godot,godotengine/godot,ex/godot,Zylann/godot,josempans/godot,akien-mga/godot,BastiaanOlij/godot,guilhermefelipecgs/godot,ex/godot,DmitriySalnikov/godot,DmitriySalnikov/godot,vnen/godot,josempans/godot,sanikoyes/godot,josempans/godot,firefly2442/godot,ZuBsPaCe/godot,Shockblast/godot,Faless/godot,vkbsb/godot,Paulloz/godot,ZuBsPaCe/godot,Faless/godot,guilhermefelipecgs/godot,Paulloz/godot,vkbsb/godot,sanikoyes/godot,honix/godot,Zylann/godot,pkowal1982/godot,josempans/godot,Shockblast/godot,firefly2442/godot,Valentactive/godot,vnen/godot,Faless/godot,DmitriySalnikov/godot,guilhermefelipecgs/godot,sanikoyes/godot,DmitriySalnikov/godot,josempans/godot,BastiaanOlij/godot,honix/godot,akien-mga/godot,vnen/godot,josempans/godot,Zylann/godot,Zylann/godot,akien-mga/godot,Paulloz/godot,Valentactive/godot,guilhermefelipecgs/godot,MarianoGnu/godot,DmitriySalnikov/godot,sanikoyes/godot,godotengine/godot,guilhermefelipecgs/godot,MarianoGnu/godot,DmitriySalnikov/godot,MarianoGnu/godot,BastiaanOlij/godot,pkowal1982/godot,ex/godot,BastiaanOlij/godot,Faless/godot,firefly2442/godot,pkowal1982/godot,vkbsb/godot,Shockblast/godot,ZuBsPaCe/godot,Valentactive/godot,firefly2442/godot,ZuBsPaCe/godot,Zylann/godot,ZuBsPaCe/godot,josempans/godot,sanikoyes/godot,BastiaanOlij/godot,akien-mga/godot,pkowal1982/godot,akien-mga/godot,MarianoGnu/godot,BastiaanOlij/godot,Valentactive/godot,godotengine/godot,MarianoGnu/godot,honix/godot,Paulloz/godot,Shockblast/godot,pkowal1982/godot,Zylann/godot,ex/godot,akien-mga/godot,vkbsb/godot,Valentactive/godot,vkbsb/godot,Paulloz/godot,firefly2442/godot,pkowal1982/godot,akien-mga/godot,Faless/godot