Add GAP type hierarchy exporter and json example output

gap/gaptypes.g

+LoadPackage("json");
+
+GAPFilterToFilterType := function(fid)
+    if INFO_FILTERS[fid] in FNUM_CATS then
+        return "GAP_Category";
+    elif INFO_FILTERS[fid] in FNUM_REPS then
+        return "GAP_Representation";
+    elif INFO_FILTERS[fid] in FNUM_ATTS then
+        return "GAP_Attribute";
+    elif INFO_FILTERS[fid] in FNUM_PROS then
+        return "GAP_Property";
+    elif INFO_FILTERS[fid] in FNUM_TPRS then
+        return "GAP_Tester";
+    else
+        return "GAP_Filter";
+    fi;
+end;
+
+# Make GAP Type graph as a record
+GAPTypesInfo := function()
+    local  res, lres, i, ff;
+
+    res := rec();
+
+    for i in [1..Length(FILTERS)] do
+        if IsBound(FILTERS[i]) then
+            lres := rec();
+
+            lres.type := GAPFilterToFilterType(i);
+
+            ff := TRUES_FLAGS(WITH_IMPS_FLAGS(FLAGS_FILTER(FILTERS[i])));
+            lres.implied := List(ff,
+                               function(f)
+                                   if IsBound(FILTERS[f]) then
+                                       return NAME_FUNC(FILTERS[f]);
+                                   else
+                                       return "<<unknown>>";
+                                   fi;
+                               end);
+            res.(NAME_FUNC(FILTERS[i])) := lres;
+        fi;
+    od;
+
+    return res;
+end;
+
+# Write the graph of type info to JSon file
+GAPTypeToJson := function(file)
+    PrintTo(file, GapToJsonString(GAPTypesInfo()));
+end;
+