Added validator for locales based on all strings in the source code.

It checks:
 - whether all keys used by the program are in the locale
 - whether the right number of %s are used
 - if there are no extra keys in the locale that shouldn't be there
This will become very useful when translations need to be updated for new MSE versions.

There is a perl script for generating the 'expected_locale_keys' resource file.
This file contains a list of all the locale keys used.
This is a resource and not a data file because it is automatically generated from the code,
 the user has no business modifying it.

I also fixed all the locale errors I found in the process.

git-svn-id: svn://svn.code.sf.net/p/magicseteditor/code/trunk@613 0fc631ac-6414-0410-93d0-97cfa31319b6

src/data/format/apprentice.cpp

@@ -697,7 +697,7 @@ void ApprenticeExportWindow::onOk(wxCommandEvent& ev) {
 		}
 	} catch (const AbortException&) {
 		// aborted, cleanup is already handled by dtors
-		wxMessageBox(_LABEL_("apprentice export cancled"), _TITLE_("export canceled"), wxOK | wxICON_INFORMATION);
+		wxMessageBox(_LABEL_("apprentice export cancelled"), _TITLE_("export cancelled"), wxOK | wxICON_INFORMATION);
 	}
 	// Done, close progress window
 	progress_target->Hide();