Use underscores instead of spaces for all internal names. And renamed some script functions at the same time.

* cannocial_name_form now outputs "_", where it used to use " "
* this simplifies reflectio and scripting code, because now C++ names are also MSE internal names
* added 'caption' property to fields. This is used instead of the name in NativeLookEditor, since the latter will now contain underscores.
* renamed text related script functions for consistency, since we were touching that part of the code anyway.

src/script/script.cpp

@@ -58,7 +58,7 @@ void init_script_variables() {
   Var(in);
   Var(match);
   Var(replace);
-  VarN(in_context,_("in context"));
+  Var(in_context);
   Var(recursive);
   Var(order);
   Var(begin);
@@ -72,7 +72,7 @@ void init_script_variables() {
   Var(set);
   Var(game);
   Var(stylesheet);
-  VarN(card_style,_("card style"));
+  Var(card_style);
   Var(card);
   Var(styling);
   Var(value);