- changed parameter type mismatch responses from assertions to warnings
- fixed setting outliers parameter as int instead of boolean
- added some tests picture preview settings to test_file_parse_key()
- use existing raster data for XYZ previews when possible
- added a function to get preview settings from File just as the actual values
- fixed item_changed() to not blindly assume anything corresponding to PICTURE file piece is the
- updated GTypes in file piece table
- implemented loading and remembering image preview generation settings from and to File