adding ignored failures for #86
Software versions, requirements in separate tables

Put the versions for software into their own table, such that every
software can have various versions. Greater-than and less-than relations
between versions can now be made using the rank column

Jobs and Jobtypes now no longer depend on software by directly linking
to the software table, but rather by using a software requirements
table, which can optionally specify min and max versions.
Remove AJAX loader for software for Jobs

With the latest changes to the database model, this no longer works
Adapt tests to recent changes in database model
Try to fix tests on travis

Import the new models in testutil.py
Use IDTypeWork for JobType.id