Collision handling for hash table

[PaMeirelles]

void storeHashEntry(const Board &b, const Move &m, const int score, const int depth, const char flag, HashTable * hashTable){
    if(m.from < 0){
        throw runtime_error("Invalid move");
    }
    const U64 key = hashBoard(b);
    const U64 index = key % hashTable->numEntries;
    if(hashTable->pTable[index].hashKey == 0){
        hashTable->newWrite++;
    }
    else{
        hashTable->overWrite++;
    }
    hashTable->pTable[index].depth = depth;
    hashTable->pTable[index].score = score;
    hashTable->pTable[index].flag = flag;
    hashTable->pTable[index].move = m;
    hashTable->pTable[index].hashKey = key;
}