Update space dispatch:

- drawXXXspace, changeXXXspace, and winqreadXXXspace now receive the area
     and spacedata as explicit arguments, allowing them to access private
     data w/o going through globals.
 - pass the new BWinEvent through to the winqreadXXXspace, allowing future
     access to extended event data.

Removed direct calls to winqreadXXXspace to simulate user actions, replaced
by calls to action functions in edit.c or the appropriate handler.

source/blender/include/BSE_drawview.h

@@ -36,6 +36,7 @@
 struct Object;
 struct BGpic;
 struct rcti;
+struct ScrArea;
 
 void setalpha_bgpic(struct BGpic *bgpic);
 void default_gl_light(void);
@@ -44,7 +45,7 @@ void two_sided(int val);
 void circf(float x, float y, float rad);
 void circ(float x, float y, float rad);
 void backdrawview3d(int test);
-void drawview3dspace(void);
+void drawview3dspace(struct ScrArea *sa, void *spacedata);
 void drawview3d_render(struct View3D *v3d);
 int update_time(void);
 void calc_viewborder(struct View3D *v3d, struct rcti *viewborder_r);