Function hm::do_tasks

pub fn do_tasks(a: HashMap<String, ManagedObject>) -> Result<(), HMError>

Take our list of ManagedObjects to do stuff to, and determine if they're simple or complex (simple is symlink or copy, complex maybe compilation or pulling a git repo). We just do the simple ones, as they won't be computationally expensive.

For complex ones we get a list of list of MOs that we can do in some order that satisfies their dependencies, then we hand them off to send_tasks_off_to_college().