* closes#22 (missing CloseHandle for FreeDOS' AUTOEXEC.BAT)
* split rufus and rufus_fd solution files (VS2010)
* error messages small improvements
* since we're on Windows, use .txt extension for README and TODO
* progress bar now reflects actual completion of process more closely
* dropped the use of UM_FORMAT_PROGRESS and introduced UpdateProgress() instead
* also reduced the number of rw test patterns from 4 to 2
* after a bb check, MBR could become garbage
* when that occurs, Windows might interpret a bad partition table and prevent MBR from being properly written
* force a complete zeroing of the whole MBR before partitioning to fix this
* also added error code for bb