Latin grammar: clean up and update

This patch removes all superfluous files from the directory, especially the
binary files in the doc folder. They are still available in the git
repository http://github.com/daherb/GF-latin which is still the main
repository for the development of the latin grammar.
The GF files are updated to a state close to the one at the end of the GF
Summer School 2015 where they were extended to support the MUSTE grammar.

src/latin/AdverbLat.gf

@@ -1,6 +1,7 @@
-concrete AdverbLat of Adverb = CatLat ** open ResLat, Prelude in {
+concrete AdverbLat of Adverb = CatLat ** open ResLat, Prelude in
+  {
 
---  lin
+  lin
 --    PositAdvAdj a = {s = a.s ! AAdv} ;
 --    ComparAdvAdj cadv a np = {
 --      s = cadv.s ++ a.s ! AAdv ++ "than" ++ np.s ! Nom
@@ -9,11 +10,16 @@ concrete AdverbLat of Adverb = CatLat ** open ResLat, Prelude in {
 --      s = cadv.s ++ a.s ! AAdv ++ "than" ++ s.s
 --      } ;
 
---    PrepNP prep np = {s = appPrep prep np.s} ;
+--  PrepNP : Prep -> NP -> Adv ;        -- in the house
+    PrepNP prep np = {s = prep.s ++ np.s ! prep.c } ;
 
 --    AdAdv = cc2 ;
---
---    SubjS = cc2 ;
+
+-- Subordinate clauses can function as adverbs.
+
+--  SubjS  : Subj -> S -> Adv ;              -- when she sleeps
+    SubjS = cc2 ;
+    
 -----b    AdvSC s = s ; --- this rule give stack overflow in ordinary parsing
 --
 --    AdnCAdv cadv = {s = cadv.s ++ "than"} ;