rename run to apply
task_class option
no default args
refactor task_description
refactor LazyChannel
Merge branch 'master' of github.com:cenkalti/kuyruk into docs

* 'master' of github.com:cenkalti/kuyruk:
  refactor LazyChannel
  refactor task_description
  no default args
  task_class option
  rename run to apply
docs