For peer review.

For peer review.
Added two new hash manipulation functions.
int SetHashPosFromKey(HashList *Hash, const char *HKey, long HKLen, HashPos *At);
int DeleteEntryFromHash(HashList *Hash, HashPos *At);

First one searches for the Key and updates the HashPos to point at it.
Second one deletes an entry from the hash, entry is pointed to by HashPos