Add doc/dependency_tree. 'cd doc/dependency_tree && tree opencoarrays' now ddepicts the OpenCoarrays dependency tree.
Add doc/dependency_tree. 'cd doc/dependency_tree && tree opencoarrays' now ddepicts the OpenCoarrays dependency tree.

Signed-off-by: Damian Rouson <81506e60eee71dc76c4134679bb4df3d66491c5e@rouson.net>

sourceryinstitute/opencoarrays,zbeekman/opencoarrays,jerryd/opencoarrays,jerryd/opencoarrays,zbeekman/opencoarrays,sourceryinstitute/opencoarrays,zbeekman/opencoarrays,jerryd/opencoarrays,sourceryinstitute/opencoarrays