Make patching HTTP(S)_PROXY configurable #9
Description
Currently we unconditionally change $HTTP_PROXY and $HTTPS_PROXY env vars to point to Hoverfly. However, as was noted in #3 (comment), it may not always be desirable. We should at least allow disabling this behavior via an argument to @hoverfly.
We should also provide a recipe for how to point common HTTP libraries to Hoverfly explicitly.