pro drops and 'how AP' in Extra for some languages

src/english/ExtraEng.gf

@@ -93,4 +93,8 @@ concrete ExtraEng of ExtraEngAbs = CatEng **
 
     ConjVPS = conjunctDistrTable Agr ;
 
+    ICompAP ap = {s = "how" ++ ap.s ! agrP3 Sg} ; ---- IComp should have agr!
+
+    IAdvAdv adv = {s = "how" ++ adv.s} ;
+
 } 

src/english/ExtraEngAbs.gf

@@ -1,4 +1,4 @@
-abstract ExtraEngAbs = Extra ** {
+abstract ExtraEngAbs = Extra - [ProDrop] ** {
 
 -- uncontracted negations; contracted are the default
   fun