CHashFile

This forms the lower-level, disk-based database that TinyMUX uses.

CHashFile uses CHashPage and adds extendible hashing and the ability to cache CHashPages. The complete set of CHashPages are kept in the netmux.pag file. A subset of these pages are cached in memory. The netmux.dir file is the directory from the extendible hashing. It's read at startup, and written after page and directory splits modify the in-memory version, but otherwise, it's not used while the game is running.