Add support for no_proxy env var

This change allows puppet to respect the no_proxy ENV var when set on the system. Previously, Puppet would respect the http(s)_proxy ENV var when connecting HTTP services (e.g. puppet forge) but ignore the no_proxy setting. Documentation is a bit inconsistent with regards to specifying domain level exception. WGET docs for example, state that the no_proxy list should be of suffixes and thus an entry with a preceding '.' (e.g. .example.com) creates an exception for any host under that domain. Curl man pages and other internet resources, suggest the use of a '*' as a wildcard. This change supports both notations.