(svn r15027) -Merge: tomatos and bananas left to be, here is NoAI for all to see.

NoAI is an API (a framework) to build your own AIs in. See:
   http://wiki.openttd.org/wiki/index.php/AI:Main_Page
 With many thanks to:
  - glx and Rubidium for their syncing, feedback and hard work
  - Yexo for his feedback, patches, and AIs which tested the system very deep
  - Morloth for his feedback and patches
  - TJIP for hosting a challenge which kept NoAI on track
  - All AI authors for testing our AI API, and all other people who helped in one way or another
-Remove: all old AIs and their cheats/hacks

src/ai/api/ai_date.cpp

@@ -0,0 +1,47 @@
+/* $Id$ */
+
+/** @file ai_date.cpp Implementation of AIDate. */
+
+#include "ai_date.hpp"
+#include "../../date_func.h"
+
+/* static */ int32 AIDate::GetCurrentDate()
+{
+	return ::_date;
+}
+
+/* static */ int32 AIDate::GetYear(int32 date)
+{
+	if (date < 0) return -1;
+
+	::YearMonthDay ymd;
+	::ConvertDateToYMD(date, &ymd);
+	return ymd.year;
+}
+
+/* static */ int32 AIDate::GetMonth(int32 date)
+{
+	if (date < 0) return -1;
+
+	::YearMonthDay ymd;
+	::ConvertDateToYMD(date, &ymd);
+	return ymd.month + 1;
+}
+
+/* static */ int32 AIDate::GetDayOfMonth(int32 date)
+{
+	if (date < 0) return -1;
+
+	::YearMonthDay ymd;
+	::ConvertDateToYMD(date, &ymd);
+	return ymd.day;
+}
+
+/* static */ int32 AIDate::GetDate(int32 year, int32 month, int32 day_of_month)
+{
+	if (month < 1 || month > 12) return -1;
+	if (day_of_month < 1 || day_of_month > 31) return -1;
+	if (year < 0 || year > MAX_YEAR) return -1;
+
+	return ::ConvertYMDToDate(year, month - 1, day_of_month);
+}