Show VCS log

[mgorny]

From https://bitbucket.org/mgorny/smart-live-rebuild/issues/12/show-vcs-log:

Bitbucket user created an issue 2016-04-21
It would be nice to be able to display commit logs for commits after the installed one. I know that at least for git it would mean doing a shallow clone instead of just "ls-remote"... oh well. AFAIK, it could also be special-cased for github, which apparently provides API to remotely query logs. Maybe other git hosts do this as well. I would be even willing to implement this myself if you outline your architectural vision.