0, 4, 0, 'beta', 5

added cryptographic signing of version number in forms.VersionField to avoid data tampering
code clean
- removed check for concurrency if pk == None
- added test for creation
added signing.py
0.4b6
0.4b7
- fixed bug that prevent concurrenty to work if pk==0
- code clean
minor refactoring and fixed default value of VersionField