Add AI/GS methods to get inflation factors

See: #415

src/script/api/script_inflation.hpp

@@ -0,0 +1,35 @@
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file script_inflation.hpp Inflation related code. */
+
+#ifndef SCRIPT_INFLATION_HPP
+#define SCRIPT_INFLATION_HPP
+
+#include "script_object.hpp"
+
+/**
+ * Class that handles inflation related functions.
+ * @api ai game
+ *
+ */
+class ScriptInflation : public ScriptObject {
+public:
+	/**
+	 * Get the inflation factor for prices.
+	 * @return Inflation factor, 16 bit fixed point.
+	 */
+	static int64 GetPriceFactor();
+
+	/**
+	 * Get the inflation factor for payments.
+	 * @return Inflation factor, 16 bit fixed point.
+	 */
+	static int64 GetPaymentFactor();
+};
+
+#endif /* SCRIPT_INFLATION_HPP */