[FEATURE] - Additions and changes to Layout Editor

[Vladabdf]

This issue includes feature requests as well as bugs, but as there are more features than bugs I would like to mark it as an enhancement. As such, the details are as follows:

Enhancements:

• Add animation layer reordering through click & drag or an up/down position button
• Extend the sprite group preview window by a few pixels in all directions to prevent cut off from occurring (https://i.vgy.me/43QdNh.png)
• Add a zoom option for all preview windows in the editor
• Change the 4:3 and 16:9 bounding box display to overlay on top of the animations so they are easier to see
• Add the 4:3 and 16:9 bounding box display to the sequence editor
• Add the option to specify the location of the msg folder to render in text that is called from animation groups
• Add "add sprite" and "remove sprite" buttons to the sprite editor

Bugs:

• UV Animation values in the sprite editor do not work when changed (They read correctly from vanilla files, but changing them to a non-0 value causes them to stop working upon saving. Adding new non-0 values do not work whatsoever)
• Fix clicking through sub-windows