clean up and fix deletion of plans
* plans which have been created in one run can be deleted fixes #95
* upload of results does not fail any more for plans created in one run fixes #85

the root cause for both was how alternatives have been stored: with each "save" or "proceed" copies of experiment and dependent classes were created - these remained in the database and caused the foreign key constraint violations,
and made the result objects "disappear".

* fixes #109, in Run Experiments the report can be edited (instead of the form the surrounding popup panel was rerendered, which broke ajax ..)

These fixes require the plato database to be recreated