rem: BPlusTree::Remove(Transaction *transaction, const char *key, off_t value)
add: BPlusTree::Remove(Transaction &transaction, const char *key, off_t value)
context: BPlusTree::Remove(Transaction *transaction, const char *key, off_t value){	if (fHeader->data_type != BPLUSTREE_STRING_TYPE)		return B_BAD_TYPE;	return Remove(transaction, (uint8 *)key, strlen(key), value);}