Add support for LBRY

Extract all URLs from webpage head since we have no access to body when
JS is not available.

Thanks to Sanja Jotić <sj@sanja-jotic.from.hr> for experimentation and
prototyping that enabled this implementation.

docs/supportedsites.md

@@ -416,6 +416,7 @@
  - **la7.it**
  - **laola1tv**
  - **laola1tv:embed**
+ - **LBRY**
  - **LCI**
  - **Lcp**
  - **LcpPlay**

youtube_dl/extractor/extractors.py

@@ -528,6 +528,7 @@ from .laola1tv import (
     EHFTVIE,
     ITTFIE,
 )
+from .lbry import LBRYIE
 from .lci import LCIIE
 from .lcp import (
     LcpPlayIE,

youtube_dl/extractor/lbry.py

@@ -0,0 +1,61 @@
+# coding: utf-8
+from __future__ import unicode_literals
+
+import re
+
+from .common import InfoExtractor
+
+
+class LBRYIE(InfoExtractor):
+    _VALID_URL = r'https?://(?:www\.)?lbry\.tv/@(?P<uploader_url>[^/?#&]+:[0-9a-f]+)/(?P<title_url>[^/?#&]+:[0-9a-f]+)'
+    _TEST = {
+        'url': 'https://lbry.tv/@MimirsBrunnr:8/sunne-light-of-the-world-summer-solstice:6',
+        'md5': '18e0cf991d0a9db3e23e979c20ed40a1',
+        'info_dict': {
+            'id': '62b95f07397a291d16e911ce7eb7c816a6992202',
+            'ext': 'mp4',
+            'title': 'Sunne, Light of the World (Summer Solstice)',
+            'title_url': 'sunne-light-of-the-world-summer-solstice:6',
+            'thumbnail': 'https://thumbnails.lbry.com/gtsvh8nQLHA',
+            'uploader': 'Mimir\'s Brunnr',
+            'uploader_url': 'MimirsBrunnr:8'
+        }
+    }
+
+    def _real_extract(self, url):
+        mobj = re.match(self._VALID_URL, url)
+
+        uploader_url = mobj.group('uploader_url')
+        title_url = mobj.group('title_url')
+
+        webpage = self._download_webpage('https://lbry.tv/@%s/%s' % (uploader_url, title_url), uploader_url + '+' + title_url)
+        webpage_uploader = self._download_webpage('https://lbry.tv/@%s' % uploader_url, uploader_url)
+
+        title = self._html_search_regex(r'<title>(.*?)</title>', webpage, 'title', default=None) or \
+            self._og_search_property('title', webpage)
+        thumbnail = self._og_search_property('image', webpage)
+        uploader = self._html_search_regex(r'<title>(.*?)</title>', webpage_uploader, 'uploader', default=None) or \
+            self._og_search_property('title', webpage_uploader)
+
+        embed_url = self._og_search_property('video', webpage, default=None) or \
+            self._og_search_property('video:secure_url', webpage, default=None) or \
+            self._og_search_property('twitter:player', webpage)
+
+        video_id = embed_url.split('/')[-1]
+
+        video_type = self._og_search_property('video:type', webpage)
+        video_ext = video_type.replace('video/', '')
+
+        format_url = embed_url.replace('lbry.tv/$/embed', 'player.lbry.tv/content/claims') + '/stream?download=1'
+        formats = [{'ext': video_ext, 'url': format_url, 'vcodec': 'h264', 'acodec': 'aac'}]
+
+        return {
+            'id': video_id,
+            'ext': video_ext,
+            'title': title,
+            'title_url': title_url,
+            'thumbnail': thumbnail,
+            'uploader': uploader,
+            'uploader_url': uploader_url,
+            'formats': formats,
+        }