introduced in python3.2, this is where .pyc files are now stored, which of course makes distcheck fail. Added cleandir targets to all directories containing python code.

[master] fixed a build error due to #997: be more specific about template parameter in the test code

- add blank lines for readability
- remove white space for style consistency
- use "lower+underscore" style for variables (per the guideline)

They will be needed in future, so we don't want to change the interface
then.

Conflicts:
	ChangeLog

(not directly related to this branch but just happen to notice it)

  - pass boost::shared_ptr of IntervalTimerImpl wrapped with boost::bind
    as a handler of asio::deadline_timer
  - use boost::shared_ptr to hold pImpl