Added basic temporary evidence schema, model methods to get/put/delete it.
added a bit of documentation.
use 'path' prop of req.files file instead of 'filename'.
Added view and route allowing issuers to give badges w/ evidence.
Removing a claim code also destroys any evidence associated with it.
When showing existing codes, list number of temporary evidence items.
Merge branch 'v2.0' into issue-122-evidence-uploading

Conflicts:
	routes/index.js
Report number of evidence items and reserved-for email at /v2/unclaimed.
Added docs for GET/DELETE `/v2/claim/evidence`.
Implemented GET /v2/claim/evidence API endpoint.
Merge branch 'v2.0' into issue-122-evidence-uploading

Conflicts:
	docs/api.md
added s3 health check.
Documented AWS/fakeS3 env vars in README.md.

Also added default fake s3 storage dir to .gitignore.
Redeeming a claim code now destroys any evidence associated with it.
Changed GET /v2/claim/evidence to GET /v2/unclaimed/evidence.

Also removed DELETE `/v2/claim/evidene` from the API docs, since we're
now destroying temporary evidence upon redemption of claim codes.
Webhook now notifies client of evidence items.
Start structuring logs

* Swap out `winston` for `bunyan`
* Monkey patch `console` so it always outputs to stderr
* Add 'uncaughtException' handler and log exceptions as a fatal event
  before crashing the application.
* Implement custom request logger similar to `connect.logger()`
Fix console monkey patch for node v0.8

The way the `console` object is constructed changed between v0.8 and
v0.10. In the latest version of node the object is built from a
constructor and conveniently has _stdout and _stderr properties which
are references to streams which console will treat as stdout and
stderr. In v0.8 the console object is a singleton by virtue of the
methods being directly exported, and worse, the functions write to
process.stdout and process.stderr directly.
Loggins and Messina, together again.

And by that I mean I cobbled together a script (bin/messina.js) to
shuttle log events off to a Graylog instance (ours happens to be called
"loggins").

Note: It's mostly cobbled together by tearing apart the source of
bunyan's CLI tool. I'd like to re-write it to be more testable.
Add more information to the message in logs.