Remove unneeded files from the gem package

[orien]

There are a bunch of files in the gem package that aren't useful for downstream projects. Removing these and running the http-headers-status-v3.png image through the ImageOptim app reduces the gem package size from 424K to 293K! 🎉

gem contents diff

```diff < .gitignore CHANGELOG.md < Gemfile LICENSE README.md < RELEASING.md < Rakefile documentation/adapters.md documentation/authentication-and-authorization.md documentation/configurator.md documentation/error-handling.md documentation/examples.md documentation/how-it-works.md documentation/routes.md documentation/validation.md documentation/versioning-apis.md documentation/visual-debugger.md examples/application.rb examples/debugger.rb examples/logging.rb examples/webrick.rb lib/webmachine.rb lib/webmachine/adapter.rb lib/webmachine/adapters.rb lib/webmachine/adapters/lazy_request_body.rb lib/webmachine/adapters/rack.rb lib/webmachine/adapters/rack_mapped.rb lib/webmachine/adapters/webrick.rb lib/webmachine/application.rb lib/webmachine/chunked_body.rb lib/webmachine/configuration.rb lib/webmachine/constants.rb lib/webmachine/cookie.rb lib/webmachine/decision.rb lib/webmachine/decision/conneg.rb lib/webmachine/decision/falsey.rb lib/webmachine/decision/flow.rb lib/webmachine/decision/fsm.rb lib/webmachine/decision/helpers.rb lib/webmachine/dispatcher.rb lib/webmachine/dispatcher/route.rb lib/webmachine/errors.rb lib/webmachine/etags.rb lib/webmachine/events.rb lib/webmachine/events/instrumented_event.rb lib/webmachine/header_negotiation.rb lib/webmachine/headers.rb lib/webmachine/locale/en.yml lib/webmachine/media_type.rb lib/webmachine/quoted_string.rb lib/webmachine/request.rb lib/webmachine/rescueable_exception.rb lib/webmachine/resource.rb lib/webmachine/resource/authentication.rb lib/webmachine/resource/callbacks.rb lib/webmachine/resource/encodings.rb lib/webmachine/resource/entity_tags.rb lib/webmachine/resource/tracing.rb lib/webmachine/response.rb lib/webmachine/spec/IO_response.body lib/webmachine/spec/adapter_lint.rb lib/webmachine/spec/test_resource.rb lib/webmachine/streaming.rb lib/webmachine/streaming/callable_encoder.rb lib/webmachine/streaming/encoder.rb lib/webmachine/streaming/enumerable_encoder.rb lib/webmachine/streaming/fiber_encoder.rb lib/webmachine/streaming/io_encoder.rb lib/webmachine/trace.rb lib/webmachine/trace/fsm.rb lib/webmachine/trace/listener.rb lib/webmachine/trace/pstore_trace_store.rb lib/webmachine/trace/resource_proxy.rb lib/webmachine/trace/static/http-headers-status-v3.png lib/webmachine/trace/static/trace.erb lib/webmachine/trace/static/tracelist.erb lib/webmachine/trace/static/wmtrace.css lib/webmachine/trace/static/wmtrace.js lib/webmachine/trace/trace_resource.rb lib/webmachine/translation.rb lib/webmachine/version.rb < memory_test.rb < spec/spec_helper.rb < spec/webmachine/adapter_spec.rb < spec/webmachine/adapters/rack_mapped_spec.rb < spec/webmachine/adapters/rack_spec.rb < spec/webmachine/adapters/webrick_spec.rb < spec/webmachine/application_spec.rb < spec/webmachine/chunked_body_spec.rb < spec/webmachine/configuration_spec.rb < spec/webmachine/cookie_spec.rb < spec/webmachine/decision/conneg_spec.rb < spec/webmachine/decision/falsey_spec.rb < spec/webmachine/decision/flow_spec.rb < spec/webmachine/decision/fsm_spec.rb < spec/webmachine/decision/helpers_spec.rb < spec/webmachine/dispatcher/rfc3986_percent_decode_spec.rb < spec/webmachine/dispatcher/route_spec.rb < spec/webmachine/dispatcher_spec.rb < spec/webmachine/errors_spec.rb < spec/webmachine/etags_spec.rb < spec/webmachine/events_spec.rb < spec/webmachine/headers_spec.rb < spec/webmachine/media_type_spec.rb < spec/webmachine/request_spec.rb < spec/webmachine/rescueable_exception_spec.rb < spec/webmachine/resource/authentication_spec.rb < spec/webmachine/response_spec.rb < spec/webmachine/trace/fsm_spec.rb < spec/webmachine/trace/resource_proxy_spec.rb < spec/webmachine/trace/trace_store_spec.rb < spec/webmachine/trace_spec.rb < webmachine.gemspec ```

[0x1eef]

It strikes me as unusual to package an image in lib/. Maybe the image should be stored in documentation/diagrams/ instead.

[seancribbs]

It strikes me as unusual to package an image in lib/.

Maybe the image should be stored in documentation/diagrams/ instead.

It's used when rendering the trace resource, as the background of the canvas. There might be a better location, but it is essential content.

[0x1eef]

Looks good to me.