Notes:

The main purpose of this release is to incorporate some usability improvements for the developer and to make some small corrections. See the change-log for details.

Changes:

Sound singleton improvements, including 'Best Effort Sound Playing' (BESP) functionality for greater automation. Vector3f::angle_between and Vector3f::magnitude2 have been added. Camera::look_at added, allowing simpler Camera orientation in some cases. Executables are now copied to 'zenilib/' for convenience. Batch files have been added for cleaning the 'zenilib/' directory. A rare race condition was removed from Model. There was a small Mutex fix for Debug mode. Infinite recursion fix in negligible-width 'Text_Box'es. There are some error handling improvements. There were some small compilation fixes for GCC, as usual.