(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/fileio_type.h

@@ -19,6 +19,7 @@ enum Subdirectory {
 	GM_DIR,        ///< Subdirectory for all music
 	DATA_DIR,      ///< Subdirectory for all data (GRFs, sample.cat, intro game)
 	LANG_DIR,      ///< Subdirectory for all translation files
+	AI_DIR,        ///< Subdirectory for all AI files
 	NUM_SUBDIRS,   ///< Number of subdirectories
 	NO_DIRECTORY,  ///< A path without any base directory
 };