spell check README.rst. thanks Brett Cannon
added README.rst. to spell checker task.
added option "--single" to command `run`
MThreadRunner uses a DaemonThread to avoid process not terminating on error.
when executing task with multiprocess runner,
update task attributes from  task object in subprocess.
include list of file_dep as an implicit dependency.
update docs.

--HG--
rename : doc/tutorial/interactiveaction.py => doc/tutorial/longrunning.py
fix formatting.
fix unstable test on py3.3. and  coverage
use doit-py for coverage