move default/AI to default/python/AI

default/README.txt

@@ -5,7 +5,7 @@
 * buildings.txt, fields.txt, ship_hulls.txt, ship_parts.txt, specials.txt, species.txt, techs.txt: These define the basic content types referred to in their names. Note that species.txt often contains the effects of techs/buildings, for technical reasons. See [the FOCS specification](http://freeorion.org/index.php/Free_Orion_Content_Script_(FOCS)) for more information.
 * stringtables/, encyclopedia.txt: The first contains files all text displayed in-game (both translations and the English!), including descriptions for content. If you add just about anything, you'll need to add the entries to stringtables/en.txt for its name and descriptions. The second file lets you add custom entries to the in-game pedia as documentation (with the text itself still in stringtables/language.txt).
 * data/art/, data/sound/: Contain the audiovisual assets FreeOrion uses. New content can grab an icon from data/art/icons, or a graphic from another of the folder; there are many currently-unused files!
-* AI/: Python code to control the computer players. The AI can automatically adapt to many content changes, but some it needs to have hard-coded to successfully exploit/avoid.
+* python/AI/: Python code to control the computer players. The AI can automatically adapt to many content changes, but some it needs to have hard-coded to successfully exploit/avoid.
 * python/turn_events/: Python scripts that run at the beginning of every turn, and can trigger events that would be impossible to do purely in FOCS.
 * python/universe_generation/: Python scripts that get run at the beginning of the game and create the galaxy. You can customise the galaxy generation by editing options.py and universe_tables.py, both of which have more information in comments over there. The latter in specific controls which star types, planet types, planet sizes, and also other content get placed.
 * col_bld_gen.py: This is a script to generate col_buildings.txt, which is included by buildings.txt and should not be edited directly, from the list of species that can build colonies.

util/MultiplayerCommon.cpp

@@ -37,7 +37,7 @@ namespace {
 
         // AI Testing options-- the following options are to facilitate AI testing and do not currently have an options page widget; 
         // they are intended to be changed via the command line and are not currently storable in the configuration file.
-        db.Add<std::string>("ai-path",              UserStringNop("OPTIONS_DB_AI_FOLDER_PATH"),        "AI",     Validator<std::string>(), false);
+        db.Add<std::string>("ai-path",              UserStringNop("OPTIONS_DB_AI_FOLDER_PATH"),        "python/AI",     Validator<std::string>(), false);
         db.Add<std::string>("ai-config",            UserStringNop("OPTIONS_DB_AI_CONFIG"),             "",       Validator<std::string>(), false);
     }
     bool temp_bool = RegisterOptions(&AddOptions);