- move Chronometer class from codjo-mad-server to codjo-util
- creation of TimeSource interface to replace a call to System.currentTimeMillis() by a call to TimeSource.getTime() :
   * creation of DefaultTimeSource that simply calls System.currentTimeMillis()
   * creation of MockTimeSource to manage time measurement deterministically in tests
Merge pull request #8 from codjo-sandbox/integration

Addition of utilities for time elapsing measurement