[update] update all tutorials for truffle 4

Author: amazingandyyy

01-HelloWorld/contracts/HelloEthSalon.sol

@@ -0,0 +1,13 @@
+pragma solidity ^0.4.4;
+
+contract HelloEthSalon {
+  string message = "Hello Ethereum Salon!";
+  
+  function HelloEthSalon() {
+    // constructor
+  }
+
+  function GetMessage() returns (string) {
+    return message;
+  }
+}

01-HelloWorld/contracts/Migrations.sol

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+pragma solidity ^0.4.17;
+
+contract Migrations {
+  address public owner;
+  uint public last_completed_migration;
+
+  modifier restricted() {
+    if (msg.sender == owner) _;
+  }
+
+  function Migrations() public {
+    owner = msg.sender;
+  }
+
+  function setCompleted(uint completed) public restricted {
+    last_completed_migration = completed;
+  }
+
+  function upgrade(address new_address) public restricted {
+    Migrations upgraded = Migrations(new_address);
+    upgraded.setCompleted(last_completed_migration);
+  }
+}

01-HelloWorld/finish/migrations/1_initial_migration.js renamed to 01-HelloWorld/migrations/1_initial_migration.js

@@ -0,0 +1,4 @@
+module.exports = {
+  // See <http://truffleframework.com/docs/advanced/configuration>
+  // to customize your Truffle configuration!
+};

01-HelloWorld/truffle-config.js

@@ -0,0 +1,4 @@
+module.exports = {
+  // See <http://truffleframework.com/docs/advanced/configuration>
+  // to customize your Truffle configuration!
+};