Non-stateful tests

[k1o0]

Related to cortex-lab/alyx-matlab#52, the viewSubjectHistory test should not rely so much on the test database's state. The plan is thus:

1. For subject ZM_1087 delete all weights and water posts for the first 20 days of the animals water restriction
2. Post a load of pre-defined weights and water admins for this time period
3. Check the plots and table against a saved structure

This can only be done once the test databases are made more reliable as it would require quite a few more requests made in quick succession.

It will still be stateful in that it relies on the z-score settings for that lab and also on the mouse's water restriction record, neither of which can be changed via REST endpoint.

[k1o0]

Another suggestion: add all paths afresh each time to test addRigboxPaths