Dotmesh release-0.3.3

Fix #352 - converge diverged branches when replicating
Fix #325 - mask API keys in error messages and logs
Fix #358 - deletion attempts cause deadlock
Fix #86 - support receiving a filesystem that had been deleted

Install (docker, kubernetes): https://docs.dotmesh.com/install-setup
Upgrading: https://docs.dotmesh.com/install-setup/upgrading