Better Slic3r support and temporary STL files
Better Slic3r support
Previously, the support for Slic3r wasn't very good. Parameters that are supported by cura but not Slic3r are missing. With this version, only relevant parameters are shown. The Slic3r version used was Prusa Edition so different versions of Slic3r might behave differently.
Temporary STL files
Previously, when slicing, if you rotated or resized your model, those change would overwrite the original STL. Now, the original STL is untouched and if there are modifications to the model, those changes are saved in a temporary file for slicing.