Support for alternative reporters

To be able to run test cases in a browsers via Browserify, a more
platform independant reporter is needed. The BashReporter is also
listening on process 'exit' events and calls 'process.reallyExit' on
failure. The code unrelated to reporting functionality was moved into
'index.js'.

- Allow to configure a reporter by setting test.Reporter to a reporter
  constructor
- Added ConsoleReporter that logs to console.log, console.info,
  console.warn and console.error
- Emitting 'run' and 'completed' events in collections
- Removed 'process.reallyExit call' from BashReporter and instead
  calling 'process.exit' with the approriate exit code when the
  collection emits the 'completed' event
0.0.7
Merge pull request #3 from mantoni/master

ConsoleReporter