Still to do: signal handler for sigint/quit/term

Problems so far:
* leaks zombie processes
* does not work when terminating feh with a signal (since the convert process
  is no longer in feh's process group)

This reverts commit b257e011.

Conflicts:

	ChangeLog

Conflicts:
	src/exif.c

This reverts commit b6a1cff6.

commit 9c8226a1
Merge: e4483e5e 132ecc0f
Author: Dennis Real <github@tildepipe.org>
Date:   Sun Feb 5 17:24:17 2012 +0100

    Merge branch 'master' of ssh://github.com/reald/feh

commit e4483e5e
Author: Dennis Real <github@tildepipe.org>
Date:   Sun Feb 5 16:56:29 2012 +0100

    - improved handling of images which have exif tags but not ours
    - fixed uninitialized pointer in thumbnail mode
    - added nikon lens info if available

commit 132ecc0f
Author: Dennis Real <github@tildepipe.org>
Date:   Sun Feb 5 16:56:29 2012 +0100

    - improved handling of images which have exif tags but not ours
    - fixed uninitialzed pointer in thumbnail mode
    - added nikon lens info if available