remove the private key first if we already have a cert loaded prior to adding
it to the agent
Merge pull request #4 from synfinatic/remove-cert-b4-add

Remove private key from ssh-agent before re-adding

Works around a bug, at least in openssh on os x 10.9.2, where re-adding a private key that has a new cert puts the agent into a weird state where there are many certs loaded for a single key. In that case none of the certs work.
0.3.1 release
Expire certs in the agent; Delete direct from agent

This commit includes the agent_client module which introduces a little
bit of code for talking directly to the openssh agent. We use this now
to remove existing keys from a running agent before re-adding them. The
problem before was that ssh-add -d sometimes had trouble finding the
public key to delete. I think we can do a better job of finding the key
and more reliably remove old keys.

The get_cert module also now adds private keys with ssh-add using the -t
option which tells ssh-agent to automatically remove a key after -t
seconds. We set -t to the number of seconds between now and the expiry
of the certificate. Though this means people's ssh keys will be removed
even though only the certificate expired this doesn't seem awful.
Address review feedback, add basic tests

The basic tests are super basic. More like super simple syntax checking
really.

The review feedback is for pull request #5.
The travis build host didn't like None in setenv

Not sure why OS X allowed it.
Allow http/https urls in public key path

This is made more useful by things like this:

https://github.com/phobologic.keys

So people wouldn't have to email/IM their keys, they could be grabbed
semi-automatically.
Merge pull request #6 from cloudtools/public_on_http

Allow http/https urls in public key path
add support for:
- Issuing certificates to be valid in the future
- Overriding the default 2hr window certs can be downloaded from S3
add support for:
- Issuing certificates to be valid in the future
- Overriding the default 2hr window certs can be downloaded from S3
Merge branch 'starts-in' of github.com:synfinatic/ssh-ca into starts-in

Conflicts:
	scripts/sign_key
fix bad merge
add missing space
commit wip
Expire S3 link when cert expires
Fix bugs related to logging
Work around ssh-keygen bug related to it poorly handling DST
Update code with feedback from Mark & Mike
Add unit tests for utils.py
merge git@github.com:cloudtools/ssh-ca.git/master into starts-in
Merge pull request #7 from synfinatic/starts-in

Support future certs & keeping certs in S3 until they expire
Try Mark's py3k suggestions
pep8