Wiki-documentation for Translations

Hi,

I updated the wiki-pages related to translations. Could you please review them?
(bug 157)
As you probably know, the page https://sourceforge.net/apps/mediawiki/openpetraorg/index.php?title=Documentation_for_Translators is now linked directly from the standalone client ("Help" -> "Help improve translations").

Thank you,
Joachim

Hello Joachim,
I have now done a quick review, and adjusted the pages on the wiki slightly.

Thank you,
Timotheus