Fix UI bugs & format

This fixes a bug where lines would sometimes be incorrectly marked as unread, as well as
a bug where inbound messages would sometimes be coloured incorrectly

src/execute.c

@@ -198,8 +198,10 @@ void execute(WINDOW *w, ToxWindow *self, Tox *m, const char *input, int mode)
         return;
 
 #ifdef PYTHON
+
     if (do_plugin_command(num_args, args) == 0)
         return;
+
 #endif
 
     line_info_add(self, NULL, NULL, NULL, SYS_MSG, 0, 0, "Invalid command.");