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/functions/construction.cpp

@@ -55,5 +55,5 @@ SCRIPT_FUNCTION(new_card) {
 // ----------------------------------------------------------------------------- : Init
 
 void init_script_construction_functions(Context& ctx) {
-  ctx.setVariable(_("new card"), script_new_card);
+  ctx.setVariable(_("new_card"), script_new_card);
 }