* Add privileged updater service
* Add integration tests for updater
* Review fixes
* Move privileged updater to its own module
* Fix comments
* Interpolate registry pathnames, switch errors to AccessDenied
* Improve error handling in `waitForSingleClient`
* Use stricter DACL for named pipe
* Close `conn` on context cancellation
* Move reading update meta to separate function
* `trace.LimitExceeded` -> `trace.Errorf`
* Fix test
* Ensure updater only allows HTTPS
* Use TLS server in tests
* Fix tests