* Added an --insecure option to disable host/peer verification in libcurl.
This allows feh to load images on HTTPS hosts with self-signed certificates.
For security, this is not the default.

* Fixed an include in show_usage.

The following adds the ability, when using `feh` as a background setter,
to use a specific Xinerama screen to render a provided image. Along with
the provided '--bg-*' option, the '--xinerama-index' argument will be
used to identify the index of the detected Xinerama screen to use.

Signed-off-by: James Knight <james.d.knight@live.com>

this introduces a bug in feh_wm_set_bg, which will be fixed in the next
commit (only applies when run without HOME)

Sort filelist by modification time, newer files first. Useful for
perusing a directory of images by most recently added or changed.

Patch by sdaau on IRC. Thanks!

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)

Squashed commit of the following:

commit 55e66e15af898f4c01d7d265013124fefce795e4
Author: Daniel Friesel <derf@finalrewind.org>
Date:   Mon Sep 26 19:59:46 2011 +0200

    Save all filenames in ~/.fehbg

commit afc2774f315fc379aa96de58decf8370772036af
Author: Daniel Friesel <derf@finalrewind.org>
Date:   Mon Sep 26 19:24:38 2011 +0200

    Update test/bg --bg-fill images (off-by-one due to changed implementation)

commit bd4210cff2e895414df12868f6cab7f193c5adf5
Author: Daniel Friesel <derf@finalrewind.org>
Date:   Mon Sep 26 14:47:00 2011 +0200

    Fix feh_wm_set_bg_maxed

commit d9ada9dc2a74aef6ae0924e9c0ff296b94ee25bc
Author: Daniel Friesel <derf@finalrewind.org>
Date:   Mon Sep 26 14:39:11 2011 +0200

    Fix for non-xinerama setups

commit be2cf0f1f8c00b737e7141a372d3cbc9db4c949f
Author: Daniel Friesel <derf@finalrewind.org>
Date:   Mon Sep 26 14:24:44 2011 +0200

    Move wallpaper calculation code into separate functions

commit 4e07c1f9734569fdd778a813c5a85c63b51b3175
Author: Daniel Friesel <derf@finalrewind.org>
Date:   Mon Sep 26 13:01:46 2011 +0200

    Remove unnecessary temporary variable

commit 23d1d733b21d1560e1fbcadddc34cae3d666b21d
Author: Daniel Friesel <derf@finalrewind.org>
Date:   Mon Sep 26 12:46:25 2011 +0200

    Initial conversion, works with --bg-scale

* remove unused variable Im1 in filelist.c
* options are initialised as 0, so only explicitly set those to 0 for which it
  makes sense because of their context
* Make a few warnings about wrong option combinations fatal

Note that read_filelist used to check if its argument was an image (for people
accidentaly typing "feh -df *" instead of "feh -dF *"); this was removed
because it failed on /dev/stdin.

I might re-add it, but I'm not yet sure about the future of feh's automatic
filelist saving.

By default, feh draws white text with a black drop-shadow, which is well
readable in most, but not all cases.  The --draw-tinted option draws a
semi-transparent black box around all texts.  This improves readability, but
does not look as nice, so it won't become default behaviour.

It was suggested to use #7f7f7f7f for the background, but I decided that
for small images surrounded by a black border.