another update of the English (US) language files to match current German files

These commits update existing English language files and introduce changes that are equivalent to the changes of the German language files in commits 232eb5eddf and d1b3f0e2fe.

Contributes to issue #53 ("Full English Translation").


The code to execute one SQL query is improved, too. This is completely unrelated to the English translation, but I don't want to create another pull request for such a minor issue.