add display_context pointer to resources

This should be removed soon, it is just a short term corrective
measure for an editor segfault introduced in prior commits. The
plan is to correct the segfaults, then refactor this away.

src/display.cpp

@@ -206,6 +206,7 @@ display::display(const display_context * dc, CVideo& video, const config& theme_
 #endif
 {
 	singleton_ = this;
+	resources::disp_context = dc_;
 
 	blindfold_ctr_ = 0;
 
@@ -565,6 +566,7 @@ void display::change_display_context(const display_context * dc)
 {
 	dc_ = dc;
  	builder_->change_map(&dc_->map()); //TODO: Should display_context own and initalize the builder object?
+	resources::disp_context = dc_;
 }
 
 void display::blindfold(bool value)

src/resources.cpp

@@ -24,6 +24,7 @@ namespace resources
 	LuaKernel            *lua_kernel = NULL;
 	persist_manager      *persist = NULL;
 	game_display         *screen = NULL;
+	const display_context *disp_context = NULL;
 	soundsource::manager *soundsources = NULL;
 	std::vector<team>    *teams = NULL;
 	::tod_manager        *tod_manager = NULL;

src/resources.hpp

@@ -20,6 +20,7 @@
 class game_board;
 class game_config_manager;
 class game_display;
+class display_context;
 class gamemap;
 class game_data;
 class LuaKernel;
@@ -48,6 +49,7 @@ namespace resources
 	extern persist_manager        *persist;
 	extern game_classification    *classification;
 	extern game_display           *screen;
+	extern const display_context  *disp_context;
 	extern const mp_game_settings *mp_settings;
 	extern soundsource::manager   *soundsources;
 	extern std::vector<team>      *teams;