Check for background image allocation failure
Warn once when external key combo is used and key-handler not installed
Use real path of all files internally, requires _XOPEN_SOURCE>=500, fixes issue #137
Use a checkerboard background for alpha layer; fixes issue #138
Do not center window on screen, workaround for issue #9
Stable version 1.2
Add a section about key-handler to the man page.
Timeout initial redraw
Fix build with giflib >= 5.1.0.
Use integers for mouse mappings and buttons 6+7 for horizontal scrolling

Fixes issue #143
Merge branch 'barthalion/master'
Use thumbnails in EXIF tags; requirement for libexif is back
Small fix for thumbnail cropping
Create thumbnail cache dir automatically
Show key handler status in bar while it is running
Revised command structure and key and mouse button mappings
Added support for multiple commands per key/button mapping; elegant fix for issue #150
Revised handling of GIF animations

- New option `-a`: Play animations at startup
- Ctrl-Space toggles animation for all GIF files
- Infinite loop for all animations
Overhauled window drawing, yet again; fixes issue #155

- Buffer for window content is bigger than the window, minimizes artifacts
  when window is resized
- Back to using XSetWindowBackgroundPixmap() instead of XCopyArea(),
  no need to handle exposure events; X server can show gray background directly
  after resize event before sxiv redraws the window contents