Fix solidity linter errors

contracts/mocks/ERC827TokenMock.sol

@@ -1,13 +1,13 @@
 pragma solidity ^0.4.13;
 
 
-import '../token/ERC827Token.sol';
+import "../token/ERC827Token.sol";
 
 
 // mock class using ERC827 Token
 contract ERC827TokenMock is ERC827Token {
 
-  function ERC827TokenMock(address initialAccount, uint256 initialBalance) {
+  function ERC827TokenMock(address initialAccount, uint256 initialBalance) public {
     balances[initialAccount] = initialBalance;
     totalSupply = initialBalance;
   }

contracts/mocks/MessageHelper.sol

@@ -4,18 +4,16 @@ contract MessageHelper {
 
   event Show(bytes32 b32, uint256 number, string text);
 
-  function showMessage(
-    bytes32 message, uint256 number, string text
-  ) returns (bool) {
+  function showMessage( bytes32 message, uint256 number, string text ) public returns (bool) {
     Show(message, number, text);
     return true;
   }
 
-  function fail() {
+  function fail() public {
     require(false);
   }
 
-  function call(address to, bytes data) returns (bool) {
+  function call(address to, bytes data) public returns (bool) {
     if (to.call(data))
       return true;
     else

contracts/token/ERC827.sol

@@ -1,7 +1,9 @@
 pragma solidity ^0.4.13;
 
+
 import "./ERC20.sol";
 
+
 /**
    @title ERC827 interface, an extension of ERC20 token standard
 
@@ -11,16 +13,8 @@ import "./ERC20.sol";
  */
 contract ERC827 is ERC20 {
 
-  function approve(
-    address _spender, uint256 _value, bytes _data
-  ) public returns (bool);
-
-  function transfer(
-    address _to, uint256 _value, bytes _data
-  ) public returns (bool);
-
-  function transferFrom(
-    address _from, address _to, uint256 _value, bytes _data
-  ) public returns (bool);
+  function approve( address _spender, uint256 _value, bytes _data ) public returns (bool);
+  function transfer( address _to, uint256 _value, bytes _data ) public returns (bool);
+  function transferFrom( address _from, address _to, uint256 _value, bytes _data ) public returns (bool);
 
 }