fix -datadir=./subdir relative path,

autostart off by default except on windows,
fix occasional "vector iterator not dereferencable" assertion with msvc,
fix readlink compile warning on linux build,
use sys/param.h and BSD define instead of __BSD__,
-paytxfee switch

serialize.h

@@ -20,7 +20,7 @@ class CDataStream;
 class CAutoFile;
 
 static const int VERSION = 308;
-static const char* pszSubVer = ".3";
+static const char* pszSubVer = ".4";