(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_execmode.cpp

@@ -0,0 +1,26 @@
+/* $Id$ */
+
+/** @file ai_execmode.cpp Implementation of AIExecMode. */
+
+#include "ai_execmode.hpp"
+#include "../../command_type.h"
+
+bool AIExecMode::ModeProc(TileIndex tile, uint32 p1, uint32 p2, uint procc, CommandCost costs)
+{
+	/* In execution mode we only return 'true', telling the DoCommand it
+	 *  should continue with the real execution of the command. */
+	return true;
+}
+
+AIExecMode::AIExecMode()
+{
+	this->last_mode     = this->GetDoCommandMode();
+	this->last_instance = this->GetDoCommandModeInstance();
+	this->SetDoCommandMode(&AIExecMode::ModeProc, this);
+}
+
+AIExecMode::~AIExecMode()
+{
+	assert(this->GetDoCommandModeInstance() == this);
+	this->SetDoCommandMode(this->last_mode, this->last_instance);
+}