#71 Write protection flags not honored

The write protection flags IS_DF_HARD_WRITE_PROTECT and IS_DF_SOFT_WRITE_PROTECT do not get honored to determine if a volume should be presented as readonly to the Linux OS. For my own project (TruPax) disk volumes get created and mounted as hard drives - on all modern OSes they become readable and writable. If the aforementioned flags are set Windows and OSX will treat the mounts as readonly - only under Linux writing is still possible.