Housekeeping tasks default to current module (#50)
Housekeeping tasks default to current module (#50)

* Change the default deferred task target to the current module.

This allows you to use the housekeeping tasks for the search index without
having to define WORKER_MODULE_NAME in your settings or setup modules for
your app.

* Removed unused imports, use lazy formatting in logging messages.

Having a separate logger instance makes it easy to suppress messages
from the search package (if necessary).

* Import the deferred module instead of `defer` directly.

Mainly cos this makes it a lot simpler to mock out deferred calls
in a codebase. If all modules use `deferred.defer()` then your mock
could work on `google.appengine.ext.deferred` instead of having to
mock each module separately.

davidwtbuxton/search,potatolondon/search,davidwtbuxton/search,potatolondon/search