Change the default for commits to revision view

One of the biggest complaints we've received is that it takes too many
clicks to get from the repo index page to actually view some source
code. So, when clicking on a revision, show the tree.

This replaces the log view as the default for a branch, which
apparently users didn't find very useful (but we may add back as an
additional link as part of rethinking the repo index page).

Change-Id: I3d69dabd34643fa3664fa00877d11ea38c48de4a
4 files changed