remove urlopen/RequestStr

[jamesturk]

these are holdovers from a pre-requests era and should go away now.

attributes of RequestStr resp:

• treating resp like a string (use resp.text)
• _scraper - can go away, was 'private'
• resp.bytes -> new.content
• resp.response -> new
• resp.encoding -> new.encoding
• resp.response.requested_url -> new.history[0].url if new.history else new.url
• resp.response.code -> new.status_code