Gif Sequencing v1.2!

Hey there! This is an update to fix a bug that affected larger files / more complex sequences. I believe the bug is now fixed. Big shoutout to @Smalusion on Twitter for helping me debug the issue by sending me the problematic file and doing some testing for me!

This update also adds a feature where the extension will list all of the missing tags in a preset if it is missing tags at all.