The new implementation will store the master password in the keyring instead of storing each and every server password separately. The master password will be used to encrypt/decrypt server password when storing in the pgAdmin config DB.
1) Replace the deprecated unit test method.
2) Wraps filter usage in a list call.
3) Converts the old metaclass syntax to new.
4) Use range instead of xrange method.
5) Change Unicode to str.
6) Several other transformations.
7) Fixed change password test cases.
8) Use simplejson instead of plain JSON.
