Changelog for Version 2.9 (Rev.2)

- refactored I/O code (got rid of iomanX/fileXio stuff). This is actually
a first step to the new I/O subsystem that I am planning to implement;
- fixed glitch in 1080i video mode;
- fixed power off problem;
- chnaged A/V synchronization code yet again in order to prevent application
lock-up for badly interleaved .avi files;
- added functionality to configure "reset" button action (power-off/exit) in
"SMS menu -> Browser settings";