Open links in browser

Open links in configuration UI in internal browser (unless Eclipse is
configured to use an external one).
Cleanup: move generic Util classes, cleanup copyrights

Move generic Util classes into a separate util package.
Update copyright headers of files that have changed in 2013.
Introduce new layout utility

Replace LayoutUtil with a more universal layout utility that allows
to configure SWT layouts and layout data in a fluent style. This saves
a lot of code and hopefully makes layout code easier to read and to
write.

Example using static imports:

    gridLayout( composite ).spacing( 5 );
    gridData( control ).fillBoth().span( 2, 1 );

This approach seems like a good alternative to writing dedicated
helper methods like createGridDataWithHorizontalSpan( int ) etc.
Add import and export option for config files

Add "Import" and "Export" buttons to Configuration preference and
property pages. Since .jshintrc is a hidden file, it is normally not
accessible via the Project Explorer. These buttons make it easier to
import and share config files.

Fixes #8