Gleaning issue from #52 .
Upgrading with slim release can be done if we do it manually.
Slim release is a experimental feature of reltool and release_handler does not know
about it at all (at least R16B03). So relup archive includes erts and all libraries in OTP,
we need to select necessary libraries in step 2,
(These steps are illustrated at https://github.com/shino/slim-upgrade-sample )
These steps might possibly be automated by slim-release-aware
@tsloughter why did you close this? This is a TODO ticket.