Update to 0.8.3:

Sigil 0.8.3 2015.01.31
    - 10.9.5 is now the minimum OS X version required. Only 10.10.1 has been tested.
    - -DCODE_SIGN_ID=XYZ option has been added to auto sign the app bundle on OS X.
    - Validation result plugins will auto close the Plugin Runner
      Dialog since the dialog has no real info and openes the
      validation pane with the results anyway.
    - New Plugin Preferences Support added
    - Plugins Manager will now remember last folder used
    - Support for building both Linux .deb and .rpm packages
    - Lots of Linux build support, compilation, installation, and
      documentation improvements
    - Qt 5.4 is now a minimum requirement.
    - Build changes to support update to latest Qt 5.4.0 and to
      use latest C++11 compiler
    - Numerous bugs fixed or worked around including:
      - Make Invocation of CSS W3C Online Validator more reliable
      - Fix to make Preview Window update after BookView to prevent
        memory corruption and crashes
      - Workaround Qt bug (font cache assertion) when using
        clearMemoryCaches() - see https://bugreports.qt.io/browse/QTBUG-43504
      - Properly handle loadFinsihed Signal in BookViewPreview to
        prevent clashes between BookView and Preview
      - Fix for Sigil memory use after it was freed bug
      - Workaround to the extent possible Qt bug with memory use after
        free using QWebInspectors - see https://bugreports.qt.io/browse/QTBUG-43725
      - Workaround to the extent possible Qt bug with memory use
        after free when closing MainWindows - see https://bugreports.qt.io/browse/QTBUG-43692
      - Bug fix to prevent crashes in KeyboardsShortcuts when accessing
        Preferences with multiple MainWindows

(wiz)