Exposes RequestContextFactory from the HAGD DependencyResolver
Pull update now happens on slave startup, before allowing any transactions

There was an edge case where the slave would start up and the moment the
 constructor returns, before any update pulling has happened, a bunch of
 transactions would start and all would attempt to pull updates as part
 of initializing them. If the slave was too far behind in txs, this would
 impose a considerable load on both the slave and the master, deteriorating
 service for noticeable spans of time. Moreover, most of the data transferred
 would be thrown away, as only one tx would apply the received tx stream.
 This fix makes sure that before any transactions start the slave will
 pull updates, no matter what. This is single threaded operation so it
 won't impose any extra load.

Adds a test for the above.
Removes unneeded echo from utils script