Multi-frame editing (v0.6)

Added support for multi-frame editing

1. Select any number of frames in a prefab layer
   • Frames don't need to be continuous (you can add a frame to selection by holding Shift)
2. Using the provided text field, type in a name of a tag from the prefab sprite in quotation marks or an equation that will be applied to all selected frames
   • To use frames from a tag, type in the tag name in quotation marks, like so "My Tag"
     • If more frames are selected in the root sprite than the tag frame length, the frames will cycle, e.g. [2, 3, 4, 2, 3, 4, 2, 3]
     • If fewer frames are selected in the root sprite then the tag frame length, the frames will be truncated, e.g. [2. 3]
   • Any Lua code is supported here (even functions, like math.sin(3)), so be careful not to paste malicious code
   • There are 3 special keywords
     • i - the index in the selection, starting from 1 (e.g. 1, 2, 3, 4, 5, ...)
     • f - the selected frame number (i.e. if you start the selection from frame 5 to 8, it will be 5, 6, 7, 8)
     • c - the count of the selection (the number of selected frames)
       
     • x - the current value in selected frame
3. Press the button below the text field to apply the change to selected frames
   • A live result is displayed on the button after each change in the text field
   • If there is an error with the text input, the button will be disabled

Examples:

• 4 - set all frames to 4
• 2 + 2 * 2 - set all frames to 6 (order of operations matter; you can use parenthesis ( ))
• i - set frames to [1, 2, 3, 4, ...]
• i + 2 - set frames to [3, 4, 5, 6, ...]
• c + 1 - i - set frames to [..., 4, 3, 2, 1] (reverse order)
• (i - 1) % 3 + 2 - set frames to loop back after 3rd frame (second to last number), starting from 2 (last number) - [2, 3, 4, 2, 3, 4, 2, 3, ...]
• math.sin(i) - calculate sinus from the current frame and round it to nearest whole number
• "Idle" - set frames to match frames used in tag "Idle" in the prefab