Tunnelling JSON conversion bug

When requesting a JSON object over tunnelling, somewhere along the way it converts JSON in responses and renders them useless.

For example:
`{"key": "value", "foo": null}`
gets converted to
`{"key" => "value", "foo": nil}`

":" becomes "=>" and "null" becomes "nil". Using the newest version of Beef.

The issue names no files, tests, or entry points. Start by reproducing a tunneled request for a JSON object in the newest Beef version, then trace where the response changes JSON syntax; done means tunneled JSON responses remain valid JSON with colons and null values preserved.

Written by the indexing model from the issue text.