Hack in support for the new twitter video format (#381)

This change adds ".m4s" and ".mp4" to the regex that modifies m3u8 playlist files proxied from twitter, and adds ".m4s" to the list of extensions proxied through nitter. The net effect is the new video format that twitter is using now should be supported.

src/routes/media.nim

@@ -109,7 +109,7 @@ proc createMediaRouter*(cfg: Config) =
       if getHmac(url) != request.matches[1]:
         resp showError("Failed to verify signature", cfg)
 
-      if ".mp4" in url or ".ts" in url:
+      if ".mp4" in url or ".ts" in url or ".m4s" in url:
         let code = await proxyMedia(request, url)
         check code