FAT32 caching

[DrDeano]

Currently, the FAT32 driver will write directly to the underlying stream (could be a RAM disk or a hard disk) when every a write occurs. This would update the FAT, FSInfo and short entry for the file being modified on. Additionally, when reading files, each time there is a read, the driver will re-seek and re-read the FAT from the stream. Adding caching to parts of the driver would increase speed. Caching points:

• [ ] Cache part of the FAT (as this can be big) and read new parts of the FAT when needed
• [ ] Cache the FSInfo
• [ ] Cache file entries
• [ ] Cache files entries in a directory