Method btnPrevClick

src/Ufopaedia/ArticleState.cpp:128–131

* Shows the previous available article. * @param action Pointer to an action. */

	 * @param action Pointer to an action.
	 */
	void ArticleState::btnPrevClick(Action *)
	{
		Ufopaedia::prev(_game);
	}

	/**
	 * Shows the next available article. Loops to the first.