Call set_button_state() from playsingle_controller::init_gui()

Fixes the minimap buttons sans the minimap unit/village drawing pair
being in an indeterminate overlay-less (blank) state for the duration of
the initial 'start' WML event in scenarios, unless they are interacted
with first.

set_button_state() has to be called after play_controller::init_gui()
finishes because that method calls game_display::begin() game first,
which in turn instantiates the theme UI GUI1 buttons. Notice that
set_button_state() is also called when the End Turn button is enabled
(e.g. after 'start' is finished).

The reason I'm not calling this from play_controller::init_gui()
directly is that I am concerned about possible interactions with the
replay_controller, which currently seems to do even sloppier work of the
GUI before the end of the 'start' event. I might move this call there if
that issue is sorted out, since it'll be needed for the
replay_controller anyway.

changelog

@@ -28,6 +28,9 @@ Version 1.11.15+dev:
    * Fixed the WML load error dialog not displaying an add-on name instead of
      falling back to its directory name if the add-on contains an outdated
      _info.cfg file lacking an [info]title= value.
+   * Fixed most of the minimap buttons and the End Turn button appearing
+     without contents or in the wrong state during WML start events until they
+     are interacted with or control is given to the player for the first time.
  * WML engine:
    * Fixed a regression in 1.11.14 causing WML parser/preprocessor errors to
      not interrupt the game load sequence or display an error message in-game,

players_changelog

@@ -6,6 +6,11 @@ Version 1.11.15+dev:
  * Language and i18n:
    * Updated translations:
 
+ * User interface:
+   * Fixed most of the minimap buttons and the End Turn button appearing
+     without contents or in the wrong state during WML start events until they
+     are interacted with or control is given to the player for the first time.
+
  * WML engine:
    * Fixed a regression in 1.11.14 causing WML parser/preprocessor errors to
      not interrupt the game load sequence or display an error message in-game,

src/playsingle_controller.cpp

@@ -101,6 +101,7 @@ void playsingle_controller::init_gui(){
 	gui_->scroll_to_tile(map_.starting_position(1), game_display::WARP);
 
 	update_locker lock_display(gui_->video(),recorder.is_skipping());
+	set_button_state(*gui_);
 	events::raise_draw_event();
 	gui_->draw();
 }