The FakeFluidDB class doesn't escape URI correctly thus allowing introduction of bugs that pass unit tests (e.g. PermissionsApi)

[Nicholas Tollervey]

It centres round the _generate_endpoint_url method in db.py.

GIven the following path list (as generated by PermissionsApi):

['permissions/namespaces', 'foo']

Using _generate_endpoint_url will escape the slash in the first item (between 'permissions' and 'namespaces') resulting in a path like this:

/permissions%2Fnamespaces/foo

The FakeFluidDB class simply "/".join() s them together resulting in the following (valid but incorrectly generated) path:

/permissions/namespaces/foo

In order to fix the bug in the PermissionsApi, the FakeFluidDB class should be made to mirror *exactly* the behaviour of the real FluidDB class when generating URL paths.

[Nicholas Tollervey (ntoll)]

OK... In the related branch I've also fixed the following that were causing the unit tests to fail.

1) The PermissionsApi as mentioned above
2) The AboutObjectsApi
3) The TagsApi