Remove snapshots etc from OPM reports

first commit is pretty noisy, so you might wanna just look at the other two.  Basically I removed the whole opm_tasks directory and any references to it, then moved the opm_reports directory up one and fixed the issues that came up there.  opm tests pass locally, I ran syncdb and migrate and the reports all still load fine.  @czue @sravfeyn would be interested.