Fix version error for truffle-flattener. (#794)

contracts/crowdsale/validation/IndividuallyCappedCrowdsale.sol

-pragma solidity ^ 0.4.18;
+pragma solidity ^0.4.18;
 
 import "../../math/SafeMath.sol";
 import "../Crowdsale.sol";
@@ -36,7 +36,7 @@ contract IndividuallyCappedCrowdsale is Crowdsale, Ownable {
   }
 
   /**
-   * @dev Returns the cap of a specific user. 
+   * @dev Returns the cap of a specific user.
    * @param _beneficiary Address whose cap is to be checked
    * @return Current cap for individual user
    */

contracts/crowdsale/validation/WhitelistedCrowdsale.sol

-pragma solidity ^ 0.4.18;
+pragma solidity ^0.4.18;
 
 import "../Crowdsale.sol";
 import "../../ownership/Ownable.sol";
@@ -27,9 +27,9 @@ contract WhitelistedCrowdsale is Crowdsale, Ownable {
   function addToWhitelist(address _beneficiary) external onlyOwner {
     whitelist[_beneficiary] = true;
   }
-  
+
   /**
-   * @dev Adds list of addresses to whitelist. Not overloaded due to limitations with truffle testing. 
+   * @dev Adds list of addresses to whitelist. Not overloaded due to limitations with truffle testing.
    * @param _beneficiaries Addresses to be added to the whitelist
    */
   function addManyToWhitelist(address[] _beneficiaries) external onlyOwner {
@@ -39,7 +39,7 @@ contract WhitelistedCrowdsale is Crowdsale, Ownable {
   }
 
   /**
-   * @dev Removes single address from whitelist. 
+   * @dev Removes single address from whitelist.
    * @param _beneficiary Address to be removed to the whitelist
    */
   function removeFromWhitelist(address _beneficiary) external onlyOwner {