title: Adding Yogaglo as supported youtube-dl site
body: <p>I would like to add Yogaglo support for youtube-dl.</p>
  
  <p>I've followed guidance on <a href="https://github.com/rg3/youtube-dl" rel="nofollow noreferrer">Github</a> .</p>
  
  <p>And have drafted the following:</p>
  
  <pre><code># coding: utf-8
  from __future__ import unicode_literals
  
  from .common import InfoExtractor
  
  
  class YogagloIE(InfoExtractor):
   _SIGNIN_URL = 'https://www.yogaglo.com/login'
   _PASSWORD_URL = 'https://www.yogaglo.com/login/password'
   _USER_URL = 'https://www.yogaglo.com/login/user'
   _ACCOUNT_CREDENTIALS_HINT = 'Use --username and --password options to provide yogaglo.com account credentials.'
  _NETRC_MACHINE = 'yogaglo'
  
  
  def _real_initialize(self):
      self._login()
  
  _VALID_URL = r'https?://(?:www\.)?yogaglo\.com/class/(?P&lt;id&gt;[0-9]+)'
  _TEST = {
      'url': 'https://www.yogaglo.com/class/7206',
      'md5': 'TODO: md5 sum of the first 10241 bytes of the video file (use --test)',
      'info_dict': {
          'id': '7206',
          'ext': 'mp4',
          'title': 'Have a Great Day!'
          # TODO more properties, either as:
          # * A value
          # * MD5 checksum; start the string with md5:
          # * A regular expression; start the string with re:
          # * Any Python type (for example int or float)
      }
  }
  
  def _real_extract(self, url):
      video_id = self._match_id(url)
      webpage = self._download_webpage(url, video_id)
      title = self._html_search_regex(r'&lt;h1&gt;(.+?)&lt;/h1&gt;', webpage, 'title')
  
      return {
          'id': video_id,
          'title': title,
          'description': self._og_search_description(webpage),
          'uploader': self._search_regex(r'&lt;div[^&gt;]+id="uploader"[^&gt;]*&gt;([^&lt;]+)&lt;', webpage, 'uploader', fatal=False),
          # TODO more properties (see youtube_dl/extractor/common.py)
      }
  </code></pre>
  
  <p>I've added yogagloIE to the list of extractors and when I run it I get an error that the URL is not supported. This is really a first draft and any guidance on hoe to improve it and make it work is recommended.</p>