Add a `--escape-body` option to `ronin http` command

[postmodern]

Add an option which causes the response body to printed as an escaped Ruby String. This will help when the response body is binary or contains null characters.

Example

$ ronin http --escape-body http://...
foo\0bar\0baz\0

[postmodern]

This could also be achieved by piping ronin http into ronin escape. Might not be a necessary feature.