new class PIThreadPoolLoop

libs/main/io_devices/pifile.h

@@ -85,6 +85,7 @@ public:
 	};
 	
 	//! Constructs a file with path "path" and open mode "mode"
+	//! If "path" is not empty then open file
 	explicit PIFile(const PIString & path, DeviceMode mode = ReadWrite);