vtk header for using p4est_vtk
IMPORTANT ToDo
test configuration for vtk output
print the ID to pursuit the right particle
divide update x
print ID
remove unnecessary DEBUG info
left quad DEBUG message
DEBUG only in DEBUG ;)
replace manual particle insertion by for loop

all particles are lying on a straight horizontal line beginning at 0.55
FIXBUG handle insertion when there are more than 25 particles
debug is debug is debug..
a shorter test for the video (without DEBUG messages)
Merge branch 'VTKoutput'
done writing output, see merge