fixed typos found by RETF in common directory

Just wrote a script like Topy using the RETF rules provided by
Wikipedia. A first test run on the common directory found some
more typos.

The script is available at the following URL at the moment.

https://gist.github.com/berendt/5ae38f2f1d5bd6b883d3

Also updated to active voice and changed <itemizedlist>
to <variablelist>. Removed "In order to" (useless phrase).

Change-Id: I4ecb1927e8291029db9bc0d743a3061138b974c8
Merge "fixed typos found by RETF in common directory"