Added new django tutorial for PTVS 2.0 Beta

We are keeping the existing ptvs & django tutorial "ptvs-dj.md" and titling it for PTVS 1.5 (RTM). It shows using PTVS and publishing to Cloud Services.

http://www.windowsazure.com/en-us/develop/python/tutorials/django-with-visual-studio/

This new tutorial is for 2.0 Beta "django-tutorial.md". It shows using PTVS, SQL Server, MySQL, and publishing to Cloud Services and Web Sites.  When 2.0 is out of beta, we'll take out the 1.5 tutorial.

We would like the new tutorial to be on the front Python page instead of the old tutorial.  We can just keep the old tutorial listed in the Compute page:

http://www.windowsazure.com/en-us/develop/python/compute/