Fixes and code cleanups after merge with 4.0.3

Warning handling and initial prepared statement handling (last not complete yet)
Changed a lot of functions that returned 0/1 to my_bool type.
GRANT handling now uses read/write locks instead of mutex
Change basic net functions to use THD instead of NET
(needed for 4.1 protocol)
Use my_sprintf instead of sprintf() + strlen()
Added alloc_query() to be able to chare query initialization code with
prepared statements.
Cleanup handling of SHOW COUNT(*) WARNINGS and SELECT LAST_INSERT_ID()

Note that the following test fails (will be fixed ASAP):
sub_select, union, rpl_rotate_logs and rpl_mystery22

sql/sql_do.cc

@@ -29,6 +29,6 @@ int mysql_do(THD *thd, List<Item> &values)
     DBUG_RETURN(-1);
   while ((value = li++))
     value->val_int();
-  send_ok(&thd->net);
+  send_ok(thd);
   DBUG_RETURN(0);
 }