--User changes

-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.

Source/Fractorium/OptionsDialog.ui

@@ -224,16 +224,25 @@
           <property name="text">
            <string>Use</string>
           </property>
+          <property name="textAlignment">
+           <set>AlignCenter</set>
+          </property>
          </column>
          <column>
           <property name="text">
            <string>Primary</string>
           </property>
+          <property name="textAlignment">
+           <set>AlignCenter</set>
+          </property>
          </column>
          <column>
           <property name="text">
            <string>Device</string>
           </property>
+          <property name="textAlignment">
+           <set>AlignCenter</set>
+          </property>
          </column>
         </widget>
        </item>