Autologin after account activation

[ingenieroariel]

This patch adds autologin at the end of the activation process and presents the user with the contents of the homepage so the new account process is more streamlined.

There is something we might not like and it's the use of the current mercurial tip of the django-registration package. Apart from the implemented option, there are other two alternatives, I will list the 3 of them:

1. Peg the requirements file to the current tip zip(d36a38202ee3.zip) download (option implemented)
2. Peg the requirements file to the general tip zip (tip.zip) download (would allow us to stay on top of bugfixes, but also last commit was 6 months ago)
3. Use mercurial and set it as an editable package - like we do with other Github sources (I don't like this option since it requires users to have mercurial installed when doing a build, although one could just add mercurial to the same requirements file)

[dwins]

This (potentially) complicates the build so I think we should push it back till 1.0.1 at the earliest.

[ingenieroariel]

This one should go in right after we release GeoNode 1.0

[codecov]

Codecov Report

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The diff coverage is 62.44%.

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