*.ini => *.toml. Remove unused test config.
Update the Dockerfile.
Add `-version`.
Docs: Update `config.toml` references.
Note Go 1.3 requirement and `make test`.
Use `LogWriter` to log all `http.Server` errors.
`clientMux`: Remove the implicit `Origin` check.

`websocket.Handler` implicitly checks the `Origin` header, causing
clients that do not send one (e.g., the Python WebSocket client) to
fail.
Add `ApplicationConfig.ResolveHost`.

This option is useful when running the server in a Docker container,
as other containers cannot resolve the server's hostname.
`sniffer()`: Normalize `RequestHeader.Type` case.
Add `ApplicationConfig.Origins`.

The `Origins` option specifies a list of allowed WebSocket origins. If empty
or omitted, all origins will be allowed.
README: Use mozilla-services/simplepush_test.
`validPK()`: Cherry-pick @jrconlin's fix from #88.
Merging #97.