Merge pull request #21 from akropolisio/issue-16

fix warnings

contracts/Migrations.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.23;
+pragma solidity >=0.4.24;
 
 contract Migrations {
   address public owner;

contracts/helpers/Lockable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 import './Ownable.sol';
 
@@ -19,7 +19,7 @@ contract Lockable is Ownable {
 	* @dev Modifier that disables functions by default unless they are explicitly enabled
 	*/
 	modifier whenUnlocked() {
-		require(isLocked(), "Contact is locked");
+		require(!isLocked(), "Contact is locked");
 		_;
 	}
 
@@ -28,15 +28,15 @@ contract Lockable is Ownable {
 	* @dev called by the owner to enable method
 	*/
 	function unlock() public onlyOwner  {
-		setLock(true);
+		setLock(false);
 		emit Unlocked();
 	}
 
 	/**
 	* @dev called by the owner to disable method, back to normal state
 	*/
 	function lock() public  onlyOwner {
-		setLock(false);
+		setLock(true);
 		emit Locked();
 	}
 

contracts/helpers/Ownable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 
 /**

contracts/helpers/Pausable.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 
 import "./Ownable.sol";

contracts/helpers/Whitelist.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 
 import "./Ownable.sol";

contracts/mocks/PausableMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 
 import "../helpers/Pausable.sol";

contracts/token/AkropolisBaseToken.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 import "./dataStorage/TokenStorage.sol";
 import "openzeppelin-solidity/contracts/math/SafeMath.sol";

contracts/token/AkropolisToken.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 import "./AkropolisBaseToken.sol";
 import "../helpers/Lockable.sol";
@@ -37,7 +37,7 @@ contract AkropolisToken is AkropolisBaseToken, Pausable, Lockable, Whitelist {
     * Upon construction, all calls to approve() will revert unless this contract owner explicitly unlocks approve()
     */
     function approve(address _spender, uint256 _value) 
-    public whenNotPaused  returns (bool) {
+    public whenNotPaused  whenUnlocked returns (bool) {
         return super.approve(_spender, _value);
     }
 

contracts/token/TokenProxy.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 import "./dataStorage/TokenStorage.sol";
 import "zos-lib/contracts/upgradeability/UpgradeabilityProxy.sol";

contracts/token/TokenProxyDelayed.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 import "./dataStorage/TokenStorage.sol";
 import '../upgradeability/DelayedUpgradeabilityProxy.sol';

contracts/token/dataStorage/AllowanceSheet.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 import "openzeppelin-solidity/contracts/math/SafeMath.sol";
 import '../../helpers/Ownable.sol';

contracts/token/dataStorage/BalanceSheet.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 import "openzeppelin-solidity/contracts/math/SafeMath.sol";
 import '../../helpers/Ownable.sol';

contracts/token/dataStorage/TokenStorage.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 import "./AllowanceSheet.sol";
 import "./BalanceSheet.sol";

contracts/upgradeability/DelayedUpgradeabilityProxy.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 import "zos-lib/contracts/upgradeability/UpgradeabilityProxy.sol";
 import "openzeppelin-solidity/contracts/math/SafeMath.sol";

contracts/upgradeability/mocks/DelayedUpgradeabilityMock.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 import "../DelayedUpgradeabilityProxy.sol";
 import '../../helpers/Ownable.sol';

contracts/upgradeability/mocks/DummyContract.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity >=0.4.24;
 
 contract DummyContractV0 {
     function hello() public pure returns(string) {