Applied patch #822935. This patch slightly increases the invalidated area during...

Applied patch #822935.  This patch slightly increases the invalidated area during a redraw request, to account for anti-aliasing.  This prevent small artifacts from being left around when text and barcode objects are dragged around the canvas.  This patch also corrects an oversight in view-barcode.c when converting from gnome_canvas_hacktext to gl_canvas_hacktext.  This patch was provided by  Emmanuel Pacaud <emmanuel.pacaud@univ-poitiers.fr>.

git-svn-id: https://glabels.svn.sourceforge.net/svnroot/glabels/trunk@315 f5e0f49d-192f-0410-a22d-a8d8700d0965