Add JSON scrape support

[WithoutPants]

Adds support for JSON scrapers. JSON scrapers work very similar to xpath scrapers, but uses GJSON to query for values. Scenes may be scraped by fragment with a query URL. The query URL supports the following parameters:

• {checksum} - the MD5 checksum of the scene
• {oshash} - the oshash of the scene
• {filename} - the base filename of the scene
• {title} - the title of the scene

A scraper for ThePornDB is below:

name: ThePornDB
performerByName:
  action: scrapeJson
  queryURL: https://metadataapi.net/api/performers?q={}
  scraper: performerSearch
performerByURL:
  - action: scrapeJson
    url:
      - https://metadataapi.net/api/performers/
    scraper: performerScraper
sceneByURL:
  - action: scrapeJson
    url:
      - https://metadataapi.net/api/scenes/
    scraper: sceneScraper
sceneByFragment:
  action: scrapeJson
  queryURL: https://metadataapi.net/api/scenes?parse={filename}&limit=1
  scraper: sceneQueryScraper
jsonScrapers:
  performerSearch:
    performer:
      Name: data.#.name
      URL:
        selector: data.#.id
        replace:
          - regex: ^
            with: https://metadataapi.net/api/performers/

  performerScraper:
    common:
      $extras: data.extras
    performer:
      Name: data.name
      Gender: $extras.gender
      Birthdate: $extras.birthday
      Ethnicity: $extras.ethnicity
      Height: $extras.height
      Measurements: $extras.measurements
      Tattoos: $extras.tattoos
      Piercings: $extras.piercings
      Aliases: data.aliases
      Image: data.image

  sceneScraper:
    common:
      $performers: data.performers
    scene:
      Title: data.title
      Details: data.description
      Date: data.date
      URL: data.url
      Image: data.background.small
      Performers:
        Name: data.performers.#.name
      Studio:
        Name: data.site.name
      Tags:
        Name: data.tags.#.tag
  
  sceneQueryScraper:
    common:
      $data: data.0
      $performers: data.0.performers
    scene:
      Title: $data.title
      Details: $data.description
      Date: $data.date
      URL: $data.url
      Image: $data.background.small
      Performers:
        Name: $data.performers.#.name
      Studio:
        Name: $data.site.name
      Tags:
        Name: $data.tags.#.tag  

[bnkai]

From a quick test it seems to work fine