Update NEWS for 1.3
Add py33 to tox.ini
Fix 2.4-incompatible line
Bump version to 1.3
Fix package version in __init__.py
Provide a __main__ entry point

Provide nose.__main__, so nose can be invoked as python -m nose

Closes: #634
Use sys.executable instead of a hard-coded 'python'
Merge pull request #635 from stefanor/executable_module

Provide a __main__ entry point