allow password to be set through WEAVE_PASSWORD env var
so that passwords can be supplied w/o them showing up in 'ps'
do not log password
This is trickier than it may first appear. We can't just filter the
password from os.Args, since that would require recreating the flag
parsing logic, which allows flags to be specified in a wide variety of
formats. And there is no API for calling that logic either.

So instead we log the results of the flag parsing, eliding the
password, and using a straight golang map for formatting (so we don't
have to get creative).
Merge branch 'master' into 276_alternative_password_supply
feed password to weave via env var, possibly via a file
The latter is the most secure route since it keeps the password
completely out of any command lines, and the permissions on the file
can be very restrictive, e.g. 0400.

It would be somewhat nicer if the password file contained just
    <password>
rather than
    WEAVE_PASSWORD=<password>
but then we'd have to transit the password via a temporary file with
0600 permissions.
Merge pull request #284 from rade/276_alternative_password_supply

LGTM.  Closes #276
update Dockerfile MAINTAINER
and also use what appears to be (based on some sampling of the docker
registry) the correct convention for specifying the email address.

Also ditch superfluous CMD instruction in weaver.
Merge pull request #283 from rade/275_do_not_log_password

Closes #275
Merge remote-tracking branch 'upstream/master' into if_param

Conflicts:
	weave
	weaver/Dockerfile