- added "hide" flag for MetaElem. Hidden MetaElem doesn't influence polygonisation.

It is useful for large scenes, when you work with lot of MetaElems. Example:

  http://e-learning.vslib.cz/~hnidek/pics/deer.jpg

  (PildaNovak's model)

- shortcuts for hiding of MetaElems:
   H ......... hide all selected MetaElems
   Shift-H ... hide all unselected MetaElems
   Alt-H ..... unhide all hidden MetaElems

- items in header menu of 3dview

source/blender/src/space.c

@@ -1262,6 +1262,14 @@ static void winqreadview3dspace(ScrArea *sa, void *spacedata, BWinEvent *evt)
 					else if(G.obedit->type==OB_LATTICE) {
 						if(G.qual==LR_CTRLKEY) add_hook();
 					}
+					else if(G.obedit->type==OB_MBALL) {
+						if(G.qual==LR_ALTKEY)
+							reveal_mball();
+						else if((G.qual==LR_SHIFTKEY))
+							hide_mball(1);
+						else if((G.qual==0)) 
+							hide_mball(0);
+					}
 				}
 				else if(G.f & G_FACESELECT)
 					hide_tface();