fix all compilation errors

contracts/access/roles/WhitelistAdminRole.sol

@@ -1,12 +1,14 @@
 pragma solidity ^0.5.0;
 
+import "zos-lib/contracts/Initializable.sol";
+
 import "../Roles.sol";
 
 /**
  * @title WhitelistAdminRole
  * @dev WhitelistAdmins are responsible for assigning and removing Whitelisted accounts.
  */
-contract WhitelistAdminRole {
+contract WhitelistAdminRole is Initializable {
     using Roles for Roles.Role;
 
     event WhitelistAdminAdded(address indexed account);
@@ -14,8 +16,10 @@ contract WhitelistAdminRole {
 
     Roles.Role private _whitelistAdmins;
 
-    constructor () internal {
-        _addWhitelistAdmin(msg.sender);
+    function _initialize(address sender) internal initializer {
+        if (!isWhitelistAdmin(sender)) {
+            _addWhitelistAdmin(sender);
+        }
     }
 
     modifier onlyWhitelistAdmin() {

contracts/access/roles/WhitelistedRole.sol

@@ -1,5 +1,7 @@
 pragma solidity ^0.5.0;
 
+import "zos-lib/contracts/Initializable.sol";
+
 import "../Roles.sol";
 import "./WhitelistAdminRole.sol";
 
@@ -9,7 +11,7 @@ import "./WhitelistAdminRole.sol";
  * crowdsale). This role is special in that the only accounts that can add it are WhitelistAdmins (who can also remove
  * it), and not Whitelisteds themselves.
  */
-contract WhitelistedRole is WhitelistAdminRole {
+contract WhitelistedRole is Initializable, WhitelistAdminRole {
     using Roles for Roles.Role;
 
     event WhitelistedAdded(address indexed account);
@@ -22,6 +24,10 @@ contract WhitelistedRole is WhitelistAdminRole {
         _;
     }
 
+    function _initialize(address sender) internal initializer {
+        WhitelistAdminRole._initialize(sender);
+    }
+
     function isWhitelisted(address account) public view returns (bool) {
         return _whitelisteds.has(account);
     }