Fix quicktime video export not properly supporting animation of audio properties like volume.

Patch #35184 by James Yonan, see the report for a detailed explanation of why this failed.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56494 954f8c5b-7b00-dc11-b283-0030488c597c
Fix for non-terminated reading of JPEG metadata

This commit prevents Blender reading memory next to non-null-terminated JPEG metadata strings


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56495 954f8c5b-7b00-dc11-b283-0030488c597c
revert part of own commit r56476, caused scene unlink button to be removed.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56496 954f8c5b-7b00-dc11-b283-0030488c597c