Update index.html back to sphinx version.

[daspecster]

Update navigation and glcoud references.

[googlebot]

We found a Contributor License Agreement for you (the sender of this pull request), but were unable to find agreements for the commit author(s). If you authored these, maybe you used a different email address in the git commits than was used to sign the CLA (login here to double check)? If these were authored by someone else, then they will need to sign a CLA as well, and confirm that they're okay with these being contributed to Google.

[googlebot]

CLAs look good, thanks!

[dhermes]

Can you give a preview of the new homepage?

[daspecster]

Site: http://daspecster.github.io/google-cloud-python
Sphinx theme: http://daspecster.github.io/google-cloud-python/latest/

I just noticed that when you click "Read the docs" the dropdown for switching languages has the wrong links in it.

[daspecster]

@dhermes, how does this look?

[dhermes]

LGTM, maybe squash commits?

ASIDE: Could you explain what happened to home.html / how much of it remains / what did it do eventually?

[daspecster]

Squshed!

home.html is for the gcloud-common doc site. It's location and name are defined in the manifest.json.

The src and json folders are all that's left from the gcloud-common site.
I can remove those as well if you want but I'll need to get our repo removed from 'deploy-docs.sh`.

[dhermes]

@daspecster I'd say you should proceed as follows (in order):

1. Remove our repo from deploy-docs.sh
2. Remove the src and json folders (and anything else that's dead) from gh-pages and do it in this PR

[daspecster]

1. Done: https://github.com/GoogleCloudPlatform/gcloud-common/pull/183
2. Done!

[dhermes]

@daspecster It seems that versions.html should stick around for old docsets:
https://googlecloudplatform.github.io/google-cloud-python/versions.html

[daspecster]

@dhermes I added versions.html back and updated the links.
I'll squash before merging if this looks good?

[dhermes]

LGTM. No need to squash, in that it could be painful.

Regarding the updating of versions.html, it's kind of the same idea as old docs versions. If they break, they break and that's OK.