Use "title" consistently in recurring tasks

The recurring task script sometimes referred to "title" and sometimes to
"text".  Use "title" consistently, and add upgrade code to fix existing
YAML files.
Merge branch 'bug/missing-title'
Allow not raising API response exceptions

When making an API call, allow the caller to request that an error not
be raised.  Probably most useful for debugging and/or in conjunction
with `decode=False`.
Handle text/html API responses
Tidy `__ne__` tests
Fix duff `__repr__` that relied on an unset value
Merge branch 'bug/bad-repr'
Make tasks a property of the user

Rather than calling `user.tasks()` to get a list of tasks, call
`user.fetch_tasks()` to update the user's list of tasks, then use one of
`user.todos`, `user.habits`, etc.  This makes little difference now, but
means we can more sensibly use the response from an API call to GET
`/user`, which returns these tasks in separate lists, as well as a
variety of other items.
Add a `user.fetch()` method

The `user.fetch()` method GETs the `/user` API method, which returns a
whole bunch of user-specific information.  At the moment we only parse
the task list, but there's now scope to expand.