Fixes a crash when a background is visible but unspecified.
Use background_exists() instead of a >=0 check.
Fix for cross-compiling on OS-X with C++11
First try at a GIF loader.
Major re-write; images load faster and bit-math is speedy.
Fixed a few bugs; most GIFs found in the wild will now load.
Better error reporting, integrated Josh's suggestions, and moved a few dubiously-named variables around.
Minor cleanup; use an inline function for clearmem(), and replace a few more pow()'s with shift arithmetic.
Fix for instance_activate_object and subclasses, done at the object level.
Merge pull request #898 from sorlok/activate_object_newfix

New fix for instance_activate_object and subclasses, done at the object level, good job! @sorlok
Merge pull request #897 from sorlok/gif_load

Animated GIF decoder.
Merge pull request #868 from sorlok/fix_no_bkgrd

Fixes a crash when a background is visible but unspecified.
Merge pull request #889 from sorlok/osx_c++11

Fix for cross-compiling on OS-X with C++11