use the new EDITOR tag to not load useless game data (units...)

when starting the editor

This seems to greatly improve the editor start time
Also use it to skip editor-groups.cfg when starting the game
Adding a GAME tag is probably nicer, but seems a bit more complex

data/_main.cfg

@@ -1,9 +1,13 @@
 {themes/}
 {core/}
 {hardwired/}		# Locations under here are wired into the C++
+
+#ifdef EDITOR
+#else
 {multiplayer/}
 {campaigns/}
 {scenario-test.cfg}
+#endif
 
 [binary_path]
     path=data/core

data/core/_main.cfg

@@ -1,9 +1,15 @@
 # Main purpose of this file is to ensure that macros get read in first.
+
+#ifdef EDITOR
+{core/terrain.cfg}
+{core/terrain-graphics/}
+{core/editor-groups.cfg}
+
+#else
 {core/macros/}
 {core/abilities.cfg}
 {core/about.cfg}
 {core/amla.cfg}
-{core/editor-groups.cfg}
 {core/fonts.cfg}
 {core/help.cfg}
 {core/hotkeys.cfg}
@@ -16,3 +22,5 @@
 {core/terrain-graphics/}
 {core/traits.cfg}
 {core/units.cfg}
+#endif
+