Clients: some improvements (#602)

* Clients: some improvements
SNIClient is the only client that uses slow_mode, so its definition should be moved there.
type info for CommandProcessor was int for some reason.
Moved a lot of type info from init to class body, making it easier for type checkers to find.
getLogger("") and getLogger(None) is technically different, just happens that our root logger is "", fixed it in case of future confusion though.

* Logging: log that init_logging was run and what the current AP version is.

SNIClient.py

@@ -128,6 +128,7 @@ class Context(CommonContext):
         self.death_state = DeathState.alive  # for death link flop behaviour
         self.killing_player_task = None
         self.allow_collect = False
+        self.slow_mode = False
 
         self.awaiting_rom = False
         self.rom = None