Pycounters

- NEW: new types of counters MaxWindowCounter, MinWindowCounter
- IMPORTANT: changes in package structure, counters module split int sub modules. Backward compatible as long as no
internals were used.
- Fixed: removing a counter by name caused an exception
- Fixed: too short queue on multi process server caused pycounters to fail if used on >~10 processes
- Fixed: starting up a new process in a multi-process auto election setup caused JSON reporter to output an empty
file (which will then be updated in the next cycle)

- Fixed - locking issue with JSON output files
- Fixed - EventCounter did not respond to events keyword argument

- added a patcher util class to allow injecting events to existing libraries/code.
- decoupled counter names from the names of events they count. Still, by default a counter will count events with
it's name
- shortcut decorators now take the name of the function they wrap as a default event name
- Added a role option to multi process reporting initializations.
- Made all report_* and shortcuts decorators usable as context managers.
- Munin plugin now ignores old reports by default
- Counters which doesn't have any value now return None instead of 0.
- Fixed an issue with aggregation of average values when not all sources had the same value
- Added output_report() to allow manual initiation of reports.

- Added a manifest.in file, so that CHANGES.txt will come along.

- Added multiprocess support.
- Extended EventLogger to allow regex based filtering of events it logs.
- Added JSONFileReporter to output reports in JSON format
- Added a utility to facilitate writing Munin plugins

- Initial Release