test: staging collector no longer returns mapping ids
util: flatten recognizes circular dependencies
Merge pull request #105 from NodeJS-agent/fix146

util: flatten recognizes circular dependencies
instrumentation: remove express4 feature flag

Refactors connect and express instrumentation to make all
middleware go the through same code.
tests: added tests for capture params in express
tests: capture params tests for hapi and restify
instrumentation: capture_params now covers query parameters as well

This normalizes our support across the frameworks. All of them
should now report route and query parameters if capture_params
is enabled.
docs: updated for new version
release: published 1.7.2