Fix deadlock in memrevcache (scionproto#1895)

The current memrevcache code will deadlock on Insert, every time: Insert
takes the write lock at the top, and later calls Get, which tries to get
the read lock. This is an automatic deadlock.

Also:
- Fix some log identifiers in go PS handlers.

PS: Add missing initialization of config (scionproto#1882)

Fix overlay port handling for BR in topology. (scionproto#1799)

It is (currently) illegal to specify `OverlayPort` in a BR entry, as the
BR doesn't run on top of the dispatcher. Additionally, calling
`OverlayAddr` on the internal address of a BR should set the overlay
port appropriately (assuming a UDP-based overlay).

Run CircleCI with machine executor and publish docker images (scionpr…

…oto#1722)

Fix misleading docstring (scionproto#1697)