Set asset url for requests from Dasher (#20)

Author: fitztrev

conf/lila.original.conf

@@ -7,6 +7,7 @@ net.site.name = "lila"
 net.domain = "localhost:8080"
 net.socket.domains = [ "localhost:8080" ]
 net.asset.base_url = "http://localhost:8080"
+net.asset.base_url_internal = "http://nginx"
 net.base_url = "http://localhost:8080"
 
 mongodb.uri = "mongodb://mongodb?appName=lila"