api.js: changed print to log at warn level
flags: Turned on postgres feature flag, updated tests for consistency
env_vars.sh: script for setting the NR_NODE_TEST_SERVICE_HOST env var to the boot2docker ip
http-agents: Log proper proxy hostname

The host property of the proxy_url object isn't created when using
proxy_host. Instead, we should be looking at the hostname property.
http-agents: Upgrade and unvendor proxying-agent

Upstream proxying-agent includes a mechanism to set the ssl certs to
connect to the proxy. This was the original reason we vendored the
module. This change upgrades to the latest upstream release and removes
the vendoring.
docs: updated for new version
release: published 1.11.0