Release 1.6

[dougwilson]

This is a tracking issue for release 1.6.

Please keep feature requests in their own issues

If you want to make a comment on a particular change, please make the comment in the "Files changed" tab so comments are not lost during a rebase.

List of changes for release:

• Accept custom 4xx and 5xx status codes in factory Support non-standard response codes #19
• Add deprecation message to "I'mateapot" export
• Deprecate passing status code as anything except first argument in factory params overloading #4
• Deprecate using non-error status codes
• Make message property enumerable for HttpErrors JSON stringified error does not contain message #20

Testing this release

If you want to try out this release, you can install it with the following commands:

$ npm cache clean http-errors
$ npm install jshttp/http-errors#1.6

Please do not merge until there is some kind of consensus / non-objection

[dougwilson]

/cc @jonathanong @dead-horse / any relevant Koa folks since this is the API for ctx.throw()

[dead-horse]

LGTM