[TW-1574] Enhancements to 'projects' report

_Paul Beckingham on 2015-03-14T17:43:14Z says:_

The `projects` report is currently not very compelling, and is simply a list of task counts by project, with an indented project list. This report could be improved to include:

* Date of earliest activity in project
* Date of most recent activity in project
* Some queue theory data: depth and average wait time
* Estimated project completion (an EBS implementation)
* Percentage project completion

If the percentage project completion is implemented, then the `projects` and `summary` reports will have essentially merged, and `summary` can be eliminated.