it will detect that you are on a topic branch base ref and
resume the topic branch creation operation.
+ In an alternative use case, if '-r BRANCH' is given instead
+ of dependency list, the topic branch is created based on
+ the given remote branch.
+
tg delete
~~~~~~~~~
Remove a TopGit-controlled topic branch of given name
In case your dependencies are not up-to-date, tg update
will first recurse into them and update these.
+ If a remote branch update brings dependencies on branches
+ not yet instantiated locally, you can either bring in all
+ the new branches from the remote using 'tg remote --populate'
+ or only pick out the missing ones using 'tg create -r'
+ ('tg summary' will point out branches with incomplete
+ dependencies by showing an '!' near to them).
+
TODO: tg update -a for updating all topic branches
TODO: Some infrastructure for sharing topic branches between