using SafeERC20 to implement safeTransfer in Crowdsale (#1006)

* introduced safeTransfer to Crowdsale

* Removed .node-xmlhttprequest-sync-7601

contracts/crowdsale/Crowdsale.sol

@@ -2,6 +2,7 @@ pragma solidity ^0.4.24;
 
 import "../token/ERC20/ERC20.sol";
 import "../math/SafeMath.sol";
+import "../token/ERC20/SafeERC20.sol";
 
 
 /**
@@ -18,6 +19,7 @@ import "../math/SafeMath.sol";
  */
 contract Crowdsale {
   using SafeMath for uint256;
+  using SafeERC20 for ERC20;
 
   // The token being sold
   ERC20 public token;
@@ -147,7 +149,7 @@ contract Crowdsale {
   )
     internal
   {
-    token.transfer(_beneficiary, _tokenAmount);
+    token.safeTransfer(_beneficiary, _tokenAmount);
   }
 
   /**
@@ -195,4 +197,4 @@ contract Crowdsale {
   function _forwardFunds() internal {
     wallet.transfer(msg.value);
   }
-}
+}