Add channel_name to videos before returning them, show on listings.

Previously, when viewing a /videos listing, there was a link
called (Chan) to bring you to the channel page, but since videos
only carried author_id and not author_name it was always kind of
ugly. This will inject that attribute on the way out.
I know, this would be more properly written as an SQL join in the
first place, but my row-dict conversion isn't set up for that and
I'm planning on converting this all to object-based returns instead
of dicts soon.

frontends/ycdl_flask/templates/channel.html

@@ -127,7 +127,7 @@ https://stackoverflow.com/a/35153397
             <span>({{video['duration'] | seconds_to_hms}})</span>
             <span>({{video['views']}})</span>
             {% if channel is none %}
-            <a href="/channel/{{video['author_id']}}">(Chan)</a>
+            <a href="/channel/{{video['author_id']}}">({{video.get('author_name', 'Chan')}})</a>
             {% endif %}
             <div class="action_toolbox">
                 <button

ycdl/ycdldb.py

@@ -256,11 +256,22 @@ class YCDLDB:
 
         query = 'SELECT * FROM videos' + wheres + orderbys
         self.cur.execute(query, bindings)
-        videos = self.cur.fetchall()
-        if not videos:
+        rows = self.cur.fetchall()
+        if not rows:
             return []
 
-        videos = [{key: video[SQL_VIDEO[key]] for key in SQL_VIDEO} for video in videos]
+        videos = []
+        channels = {}
+        for row in rows:
+            video = {key: row[SQL_VIDEO[key]] for key in SQL_VIDEO}
+            author_id = video['author_id']
+            if author_id in channels:
+                video['author_name'] = channels[author_id]
+            author = self.get_channel(author_id)
+            if author:
+                channels[author_id] = author['name']
+                video['author_name'] = author['name']
+            videos.append(video)
         return videos
 
     def insert_playlist(self, playlist_id, commit=True):