Delete(All) / Retry(All) functionality and more

Hi there,

This pull request contains

* Delete All and delete multiple jobs feature.
* Retry All and retry multiple jobs feature. Fixes #32
* View job details. 
* Fixes broken tests. Almost the same as #36

I had to change data structure so after upgrade existing users will have nothing on their Failures UI. Their data of course is not deleted, so it can be retrieved if needed.