Revert "Merge pull request #62 from vid-io/cleanup/remove-proxy-api"

This reverts commit 8011afcad35816b55dd5af5ba8f3feb697244748, reversing
changes made to 4bf85ed93f5ee47d2db39f857629b79c5d3efb71.
#via requires 2 or 4 arguments
Use a custom HTTP header to indicate if a request was proxied and clean
up proxy specs
Implement proxy support for Request objects
Bump YARDstick threshold
Merge pull request #70 from hundredwatt/proxy-support

Proxy Support