Don't actually talk to Google for the net instrumentation tests
Separate tests and helpers in XP-monitoring test file
Fix the mocking of the net instrumentation connection
Clean up assertions in the net instrumentation tests
Add implementation of Net::HTTP instrumentation events
Add a #clear method to the Agent event listener.

This is to facilitate testing event-based stuff without having to
worry about whether or not your event has been registered already.
Add request header injection for X-Tier support.

This is the outgoing HTTP request side. Incoming response side to follow.
Cut at sharing basics of service via stubs
RUBY-1016 Basic coercion class for us from to_collector_array methods
RUBY-1016 Coerce values in metric data to_collector_array
RUBY-1016 Commenting on purpose behind the NewRelic::Coerce class
RUBY-1016 Applying Coerce to thread profiling to_collector_array
Tidy up initial value setting for default_service, remove unnecessary usages
RUBY-1016 Treat Coerce as module, mix in where we want it
RUBY-1016 Better logging around coercion
RUBY-1016 Tightening up coercion on sql samples
RUBY-1016 Apply coercion to noticed errors to_collector_array
RUBY-1016 Nil strings are fine for coercion
RUBY-1016 Applying coercion to the transaction samples
RUBY-1016 Didn't include the proper types with float and string coercions