Remove entclass::clear(), simplify entclass initializations

Previously there was an entclass::clear(), and initialization of an
entclass was done by calling clear() in order to not duplicate code. But
now there's no need for an entclass::clear(), and it is in fact unused
(just call entityclass::removeentity() instead), so I'm removing this
function.

desktop_version/src/Ent.h

@@ -8,8 +8,6 @@ class entclass
 public:
     entclass();
 
-    void clear();
-
     bool outside();
 
     void setenemy(int t);