-Add a button to swap the pre and post affine values for all selected xforms.
--Bug fixes
-Remove the ability to change spinner values with +=-=, it was conflicting with other things and added no real value.
-All file dialog opening in Linux would freeze. No longer using native file dialogs, they are broken.
-Set default open path to the desktop if there is no settings file present, which will be the case on the first run.
-Amphibole_Supergroup.ugr palette had an invalid character in two of the palette names.
--Code changes
-Change some table header padding styles to work with new Qt. Qss reload is required.
-Ensure the open folder path setting always has a valid string in it before opening a folder.
-Add new palettes from user Rubydeva.
--Bug fixes
-Avoid an occasional divide by zero in the OpenCL renderer when using the interactive editor.
--Code changes
-Use exact comparisons in IsID() and IsZero() in Affine2D.
-When testing for bad point values while iterating, only test for NaN now.
-For rendering with OpenCL on the command line and in the final render dialog, use an optimized kernel that does a direct assignment for any affines which are ID.
