Maltese RG: make pro-drop explicit. Other small fixes in Structural, Lexicon.

lib/src/maltese/ExtraMltAbs.gf

@@ -4,6 +4,12 @@
 -- John J. Camilleri 2011 -- 2013
 -- Licensed under LGPL
 
-abstract ExtraMltAbs = Cat ** {
+abstract ExtraMltAbs = Cat, Extra [Pron, ProDrop] ** {
+
+  fun
+    -- SlashV2a : V2 -> VPSlash ; -- love (it)
+    SlashVa : V -> VPSlash ; -- jump (it)
+
+    -- VasV2 : V -> V2 ; --- too general for my liking
 
 }