Reorganizing Ger by smaller prepositions and separating object cases from all (N, NP, etc.) cases (#474)

* (Ger) prepositions of contracting type, to base S,VV,QS-correlates and split adverbs on

* api/TryGer: omit mkAdv,mkIAdv,mkConj from ParadigmsGer, mkStructuralGer

* (Ger) sync with 'master' (undo changes unrelated to Preposition) up to few corrections

* (Ger) correct GPl to CPl in ExtraGer

* Returning to f4aae6a61a by ignoring prep-contraction

* (Ger) Prep contracting with DefArtSg, IP, RP

* (Ger) Corrected GPl to CPl in ExtraGer, ExtendGer

* (Ger) Simplified many lincats (Prep,V2,N2,A2,.. VPSlash,ClSlash) by reducing
      Preposition from 4*3 = 12 parameters to 3*2 = 6 via
         Prepositon : Type = {s : PrepForm => Str; s2:Str ; c : ObjCase ; t : PrepType} ;
         param PrepType = isCase | isPrep ; -- isPrepDefArt
               ObjCase = Acc | Dat | Gen ;   Case = Nom | Obj ObjCase ;

src/german/MorphoGer.gf

@@ -17,8 +17,8 @@ oper
 
 -- For $StructuralGer$.
 
-  mkPrep : Str -> Case -> Preposition = \s,c ->
-    {s = \\_ => s ; s2 = [] ; c = c ; t = isPrep} ;
+  -- mkPrep : Str -> Case -> Preposition = \s,c ->
+  --   {s = \\_ => s ; s2 = [] ; c = c ; t = isPrep} ;
 
   nameNounPhrase : Gender -> {s : Case => Str} -> {s : Bool => Case => Str ;
                                                    a : Agr ;