Add a session with hard-coded parameters when "+" is clicked.
Add a session with hard-coded parameters when "+" is clicked.

This is to test that the view updates properly.

- Fix aliasing of this.templateHelpers across weeks, which caused
  "self" to return the wrong week.
- Introduce a Week model class to see if it fixed the previous problem,
  which it didn't, but we'll probably need it eventually.

6813-tracktion/gr4,6813-tracktion/gr4,6813-tracktion/6813-tracktion.github.io,6813-tracktion/6813-tracktion.github.io,6813-tracktion/6813-tracktion.github.io