Compression support added to VtkWriter

demo/init/ellipt.dat.2d

@@ -29,8 +29,7 @@ ellipt->adapt[0]->refine bisections:  2
 
 ellipt->adapt->max iteration:         10
 
-ellipt->output->filename:       output/ellipt_ascii.2d
+ellipt->output->filename:       output/ellipt.2d
 ellipt->output->ParaView format: 1
-ellipt->output->ParaView mode: 3
-ellipt->output->ARH format: 1
-ellipt->output->AMDiS format: 1
+ellipt->output->ParaView mode: 1
+ellipt->output->ARH2 format: 1