new local_commit_only target works when there is no network connection
available; merge local_commit and local_commit_only to eliminate repeated
code.
test commit: if there are no files changed, do I get an error?
added alias local-commit-only for local_commit_only in Makefile; similarly for
local-commit and local_commit.

In common.mk, added commit-only alias for commit_only
Makefile should depend on common.mk so if changes are made to common.mk, everything gets remade.

There is a problem with this, however; since common.mk is symlinked almost everywhere, Make does not seem to detect a change to the modification time of the target of the symlink. Looking for a solution to this problem.
Checked documentation; Make is supposed to look at the modification time of the target of a symlink.
Git is complaining about unstaged changes; doing a manual commit and sync.