Gas Optimizations

[code423n4]

• uint is always >= 0, can't be negative:

  function setFees(uint256 _lockIncentive)
    ...
    if (_lockIncentive >= 0 && _lockIncentive <= 30)

• No need for safe math where overflow/underflow is impossible, e.g.:

  if (_balance < _amount) {
  _amount = _withdrawSome(_gauge, _amount.sub(_balance));

• When you declared the named return value, then you do not need to return afterward explicitly:

  function withdraw(IERC20 _asset) external returns (uint256 balance) {
   ...
   return balance;

• No need to initialize to default values, e.g.:

  uint256 public periodFinish = 0;
  uint256 public rewardRate = 0;
  uint256 public queuedRewards = 0;
  uint256 public currentRewards = 0;
  uint256 public historicalRewards = 0;

• Repeated storage access should be cached, e.g. veAsset is accessed 3 times here:

        uint256 veAssetBalance = IERC20(veAsset).balanceOf(address(this));
        if (veAssetBalance > 0) {
            IERC20(veAsset).safeTransfer(staker, veAssetBalance);
        }
        //increase ammount
        uint256 veAssetBalanceStaker = IERC20(veAsset).balanceOf(staker);

[GalloDaSballo]

## No need for safe math where overflow/underflow is impossible, e.g.:
Saves 20 gas

Repeated storage access should be cached, e.g. veAsset is accessed 3 times here:

Saves 97 + 94 gas

Saves less than 500 gas