Implement basic Gantt scheduling / resource management Merged

It would be great if the Gantt chart in Releases > Roadmap had even basic scheduling built in.  Right now one can move phases/features around at will, making the chart not very useful.  ALAP (as late as possible) and ASAP (as soon as possible) scheduling based on overlapping resources and dependencies would be great, and would mean I don't need to switch to a more full-fledged Gantt tool.