Reindent source files to comply with KNF

This is the start of code-cleanups by reformatting the code using indent(1).
There's been an attempt to use .indent.pro to mimick the style(9) from
OpenBSD.  The configuration file has been included here for the future,
although it's unlikely that indent(1) will run across all these files again
as style updates can be tweaked manually.

But by including that file here, it will mean running indent(1) from the
top-level directory of MVWM will honour it.
Reindent fvwm/ to comply with KNF style

Try and match what OpenBSD style(9) does in terms of code-layout.  Should
be much more readable.