Properly handle URLs passed from command line

Previous, URL arguments passed from the command line were ignored (the
"url_list" attribute in Launcher class was unused). We now pass the list
to start-tor-browser which will open a tab with each URL.

Fix #380.

torbrowser_launcher/launcher.py

@@ -478,7 +478,7 @@ def run(self):
 
         # Run Tor Browser
         subprocess.call(
-            [self.common.paths["tbb"]["start"], "--detach"],
+            [self.common.paths["tbb"]["start"], "--detach"] + self.url_list,
             cwd=self.common.paths["tbb"]["dir_tbb"],
         )
         sys.exit(0)