Rename grass_main_0.7 to ddnet_grass

ddnet did extend the tileset so it is no longer matching the 0.7 grass_main
renaming the file makes that clear and allows for further extensions of
the file without breaking teeworlds 0.7 compability.

Also it frees the filename grass_main_0.7.png to be used by the ddnet
0.7 client mode so it can display the correct mapres on 0.7 connections.

CMakeLists.txt

@@ -1391,6 +1391,7 @@ set(EXPECTED_DATA
   editor/audio_source.png
   editor/automap/basic_freeze.rules
   editor/automap/ddmax_freeze.rules
+  editor/automap/ddnet_grass.rules
   editor/automap/ddnet_tiles.rules
   editor/automap/ddnet_walls.rules
   editor/automap/desert_main.rules
@@ -1399,7 +1400,6 @@ set(EXPECTED_DATA
   editor/automap/generic_unhookable.rules
   editor/automap/generic_unhookable_0.7.rules
   editor/automap/grass_main.rules
-  editor/automap/grass_main_0.7.rules
   editor/automap/jungle_main.rules
   editor/automap/jungle_midground.rules
   editor/automap/round_tiles.rules
@@ -1487,6 +1487,7 @@ set(EXPECTED_DATA
   mapres/bg_cloud2.png
   mapres/bg_cloud3.png
   mapres/ddmax_freeze.png
+  mapres/ddnet_grass.png
   mapres/ddnet_start.png
   mapres/ddnet_tiles.png
   mapres/ddnet_walls.png