Changelog for plot-gtk-

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0.1: * initial version * unshadowed fig in Gtk.hs * updated documentation for multiline example * bumped gtk dependency * bumped hmatrix dependency * added a destroy method * export destroy method * removed hmatrix upper dependency
* switch to github * fixed .cabal repository line * fixed .cabal repository line

0.2: * fix window behaviour by initialising once only and counting open windows to know when to quit * remove warnings from Gtk.hs:initGuiOnce