ADAL for Python 0.3.0

1. Support device code flow, required for accounts with 2FA enforced, or MSA accounts such as live id
2. Support service principal with certificate.
3. Support token cache.
4. Remove all JS style of callbacks for better code readability and maintainability.
5. Improve 'AuthenticationContext' class to be consistent with ADAL node and C# versions.
6. Add samples showing how to use the ADAL in correct ways. Convenient methods in init.py were removed as it has no integrations with cache and used client id belonging to other client app.
7. Update readme with common authentication flows and smooth package installations.
8. Update for US Government and German Government Authority.

Edit:

Note: Changes on 'client_id' and 'resource' arguments after 0.1.0

The convenient methods in 0.1.0 have been removed, and now your application should provide parameter values to client_id and resource.

2 Reasons:

• Each adal client should have an Application ID representing a valid application registered in a tenant. The old methods borrowed the client-id of azure-cli, which is never right. It is simple to register your application and get a client id. You can follow this article.

• The old method defaults the resource argument to 'https://management.core.windows.net/', now you can just supply this value explictly. Please note, there are lots of different azure resources you can acquire tokens through adal though, for example, the samples in the repository acquire for the 'graph' resource. Because it is not an appropriate assumption to be made at the library level, we removed the old defaults.