a few miscellaneous items on ExternalLocking4Reputation and Auction4Reputation

1. This in `ExternalLocking4Reputation.initialize` is redundant with what already exists in `Locking4Reputation._initialize`:

```
require(_lockingEndTime > _lockingStartTime,"_lockingEndTime should be greater than _lockingStartTime");
```

2. consider indexing the following event arguments:

- `FixedReputationAllocation.BeneficiaryAddressAdded._beneficiary`
- `Auction4Reputation.Bid._bidder`

3. `FixedReputationAllocation.enabled` will crash when `numberOfBeneficiaries` is zero:

```
beneficiaryReward = uint256(int216(reputationReward).div(int256(numberOfBeneficiaries)).fromReal());
```

Should we do a `require` with a message?