Support live zero downtime upgrades of just the binary

[jacek99]

From reading the docs on the main site, it seems the approach to zero downtime upgrades is to recompile updated source code.

This may work fine in a cloud environment, but will not work at all in a commercial on-premise software installation, where only the binaries are delivered, but never the source code.

it would be great if live reloading of binaries (without source code) was supported out of the box.