removed odd spaces and other small corrections in guide/de/ch_oview.xml
Another small correction of oview; update header of basics
Remove a few discrepancies between the german guide overview and other
components.

The components are:
a) the program, 
b) its german translation
c) the english guide
Currency movements .. remain fully balanced if "Trading Accounts" is
enabled

"double entry" was not sufficient.
Merge branch 'maint'