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/util/io/reader.hpp

@@ -181,7 +181,7 @@ class Reader {
   /** Maybe the key is "include file" */
   template <typename T>
   void unknownKey(T& v) {
-    if (key == _("include file")) {
+    if (key == _("include_file")) {
       Reader reader(this, package, value, ignore_invalid);
       reader.handle_greedy(v);
       moveNext();