invite bonus

[artman325]

the main goal are to add additional bonus tokens to person which invite buyer.
for example:
invite bonus - 5%
user1 buy 100 tokens, then we check who invite user1 in community contract.
if userX has invited user1 then userX will obtain 5% (5 tokens)
so

• need to add communityAddress into method __FundContractBase__init
  and check mapping(address => address) public invitedBy; in CommunityContract and i guees send bonus tokens to inviter maybe [here](https://github.com/Intercoin/FundContract/blob/19ed537bc2c36af507ac80aef7204ec63926e546/contracts/FundContractBase.sol#L285)
• try to migrate any timestamps data from uint256 to uint64. it will save storage

function __FundContractBase__init(
        address _sellingToken,
        uint256[] memory _timestamps,
        uint256[] memory _prices,
        uint256 _endTime,
        uint256[] memory _thresholds,
        uint256[] memory _bonuses
    ) 

UPD
replace Group logic (and method setGroup) on Community Contract logic
means for now group is a persons which was invited by user that invite buyer

Very simple
1. Make an optional parameter called “community” which is an address of CommunityContraxt
2. When Y buys, check X who invited them, if anyone. Then give bulk bonuses to array invitedBy X, including Y.