Authoritative changelog in README.md.

## Next version
- Modernization of the gem.
- Test with 100% code coverage.
- Started using Travis-CI for continuous testing.
- Started testing in various versions of active support and ruby.
- Improved documentation.

## Version 0.5.0 (Aug 6, 2012)
- Expectations can be ranges.

## Version 0.4.2 (Aug 6, 2012)
- Fixed important typo.

## Version 0.4.1 (Aug 6, 2012)
- Better error reporting (all unmatching counters).

## Version 0.4.0 (Feb 21, 2012)
- Fix crash on missing gems.
- Return what the blocks returns.

## Version 0.3.1 (Aug 25, 2011)
- Fixed documentation.

## Version 0.3.0 (Aug 24, 2011)
- Better organization of code with modules.
- Switched to bundler from jeweler.
- Removed unneeded dependencies.
- Cleaned up documentation.

## Version 0.1.0 (Oct 2, 2010)
- Initial release. Code extracted from a personal project.