Traces
Log that traces are disabled from ping.
Test traces hash initialization.
Inject net/http instrumentation.
Use traces configuration in railtie.
Fix load order of ping/railties...

...so that configuration from ping is available when initializing traces
and metrics.
Require traces to be enabled when instrumenting net/http.
Added instrument method
Instrument DelayedJob
Trace sidekiq
With a generic instrument method, Trace is now usable outside of Rails
Use old hash syntax
Fix net_http_spec
Fix missing event variable introduced by 3c9f17405.
Log trace/metrics success (debug).
Change instance method to class method, test standalone instrument.
Add the key to the hash output
Bump version
Make trace_threshold configurable