Pass "app" and "user" to TimelineApp

We're going to need this context to issue API calls from the curses UI.

toot/commands.py

@@ -76,7 +76,7 @@ def curses(app, user, args):
     else:
         generator = api.home_timeline_generator(app, user)
 
-    TimelineApp(generator).run()
+    TimelineApp(app, user, generator).run()
 
 
 def post(app, user, args):

toot/ui/app.py

@@ -300,7 +300,9 @@ class HelpModal(Modal):
 
 
 class TimelineApp:
-    def __init__(self, status_generator):
+    def __init__(self, app, user, status_generator):
+        self.app = app
+        self.user = user
         self.status_generator = status_generator
         self.statuses = []
         self.stdscr = None