phabricator: add phabupdate command to update status in batch Changing status (accept, etc) on the webpage is not very convenient - currently there is no way to accept (or abandon etc.) a stack using a single click or command. This patch adds a `phabupdate` command that could be used to change status in batch. It also supports `--comment` which will write a comment on the last revision, which is similar to what we do using emails. Differential Revision: https://phab.mercurial-scm.org/D127