v2.9.0

NEW:

1. Directly load multiple files.
2. List of plot is moved to a sidebar instead of the popup window.
3. Lock axes when working with multiple files.
4. Save fitted data.
5. Fill values can now take number of gird or grid spacing

Fixed:

2. Fixed bug with loading file directly from terminal.
3. Fixed bug in undo.
4. Fixed bug with swapper when working with multiple files.
5. Fixed bug with 3D viewer not updating