Bump version to 0.6

This was originally supposed to be 0.5.5, but with all the new features
that are supported, it seems worthy of a full point-release.

Change-Id: I1242cdf8335c1cf6c030e1ad8f9b82a6038133bc
Reviewed-on: https://gerrit.causes.com/19714
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Joe Lencioni <joe.lencioni@causes.com>