Bugfix/issue 77 handle webscrape failure

[andylitalo]

Bugfix

• Handles readings with different chapters for starting and ending verse
• Handles invalid URL, non-200 HTTP response, and failed regex parsing of HTML

Note: the readings view now returns the chapter and verses as a fully labeled dictionary, i.e., Matthew 24:1-25:3 would be returned as

{
  "Matthew": {
    "start_chapter": "24",
    "start_verse": "1",
    "end_chapter": "25,
    "end_verse": "3"
  }
}