Add a type-appropriate equality operator
Add doctest demonstrating new equality operator
Update Travis configuration:
- Python 2.5 no longer supported
- Also test against Python 3.3
Fix for comparison tests:
- equality test should not throw TypeError
- improved exception messages for __lt__ and __le__
- add custom __gt__ and __ge__; default comparison is incorrect
- added doctests
Merge pull request #1 from michel-slm/master

Add a type-appropriate equality operator