Progress!

Masked error caused by saving dbc while editor is open that causes
msg IDs to go crazy by making editor modal, but that affects all
other windows, so might be a better fix.

Added new value type of VALUE_STRING, probably better named
ENUMERATED_STRING, and it uses the table in the editor to define
the enum.

Fixed a bug in the signal viewer load when a signal is not matched
(I found it by renaming a signal and then loading)

dbc/dbcloadsavewindow.cpp

@@ -285,6 +285,7 @@ void DBCLoadSaveWindow::editFile()
     if (idx < 0) return;
 
     editorWindow->setFileIdx(idx);
+    editorWindow->setModal(true);
     editorWindow->show();
 }