The check if buffer == NULL is always false, since buffer is an
autoamtic variable allocated when entering the function.  What we
instead want to do is to check if the string is empty after the call to
exif_get_info(), since that means we could not read any exif
information.
When the code once more is enabled, I discovered that we need to copy
the information string into info_buf as well as into  buffer, since it
is the former that is used to print the exif information on top of the
picture.  Without this change, imlib warns about trying to write NULL
strings.

(cf #309)

* 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.

manually changed in collage, imlib, filelist, thumbnail, slideshow,
index
feh_display_status also changed

This means it will be treated like an HTTP image (no write operations,
copying to /tmp etc), but it's still better than no file:// support.

Also, this is why it's not documented yet.

Squashed commit of the following:

commit 58dd2e30
Merge: cf6f0320 82a976e0
Author: Dennis Real <github@tildepipe.org>
Date:   Sat Mar 31 18:43:47 2012 +0200

    Merge branch 'master' of git://github.com/derf/feh

commit cf6f0320
Merge: 10b7b1e3 877e6346
Author: Dennis Real <github@tildepipe.org>
Date:   Sun Mar 25 19:07:30 2012 +0200

    Merge branch 'master' of git://github.com/derf/feh

commit 10b7b1e3
Author: Dennis Real <github@tildepipe.org>
Date:   Sat Mar 24 14:41:15 2012 +0100

    Support for Canon Exif makernote tags

commit 3c284dc8
Author: Dennis Real <github@tildepipe.org>
Date:   Thu Mar 22 19:44:32 2012 +0100

    Support for Active D-Lightning

commit ad5aea8c
Merge: cc6de200 9c43b648
Author: Dennis Real <github@tildepipe.org>
Date:   Thu Mar 22 19:01:38 2012 +0100

    Merge remote branch 'upstream/master'

commit cc6de200
Author: Dennis Real <github@tildepipe.org>
Date:   Thu Mar 22 19:00:30 2012 +0100

    Nikon makernote parts changed

commit e401bd9c
Author: Dennis Real <github@tildepipe.org>
Date:   Wed Mar 21 19:47:15 2012 +0100

    1. Own module for nikon maker notes
    2. Support for AFInfo2

commit 39cbd1ed
Merge: 9e1bbf87 a1001232
Author: Dennis Real <github@tildepipe.org>
Date:   Fri Mar 16 22:22:28 2012 +0100

    Merge remote branch 'upstream/master'

commit 9e1bbf87
Author: Dennis Real <github@tildepipe.org>
Date:   Fri Mar 16 22:20:58 2012 +0100

    - exif handling changed
    - gps info added if available

commit 8e963828
Merge: 77fa5aca 29cd8688
Author: Dennis Real <github@tildepipe.org>
Date:   Fri Mar 16 19:13:47 2012 +0100

    Merge branch 'master' of git://github.com/derf/feh

commit 77fa5aca
Merge: 93a90e60 3b2756bf
Author: Dennis Real <github@tildepipe.org>
Date:   Wed Mar 7 17:18:07 2012 +0100

    Merge branch 'master' of git://github.com/derf/feh

commit 93a90e60
Merge: a81465d0 52d5da9c
Author: Dennis Real <github@tildepipe.org>
Date:   Tue Mar 6 21:42:40 2012 +0100

    Merge branch 'master' of git://github.com/derf/feh

commit a81465d0
Merge: a19e50de 31afac45
Author: Dennis Real <github@tildepipe.org>
Date:   Mon Mar 5 17:23:40 2012 +0100

    Merge branch 'master' of git://github.com/derf/feh

commit a19e50de
Merge: 1c89da12 fe9a16bc
Author: Dennis Real <github@tildepipe.org>
Date:   Sun Mar 4 15:35:45 2012 +0100

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

commit 1c89da12
Author: Dennis Real <github@tildepipe.org>
Date:   Tue Feb 28 22:37:22 2012 +0100

    test case adapted to new testfile

commit bb3c9d35
Author: Dennis Real <github@tildepipe.org>
Date:   Tue Feb 28 22:34:51 2012 +0100

    test file with some exif data added

commit fe9a16bc
Author: Dennis Real <github@tildepipe.org>
Date:   Tue Feb 28 22:37:22 2012 +0100

    test case adapted to new testfile

commit e0bedc04
Merge: 46801fee 69ecc5c1
Author: Dennis Real <github@tildepipe.org>
Date:   Tue Feb 28 22:36:08 2012 +0100

    Merge remote branch 'upstream/master'

commit 46801fee
Author: Dennis Real <github@tildepipe.org>
Date:   Tue Feb 28 22:34:51 2012 +0100

    test file with some exif data added