Make addAccount() internal to the VM mode

src/universal-dapp.js

@@ -42,11 +42,11 @@ UniversalDApp.prototype.reset = function (contracts, getAddress, getValue, getGa
   this.renderOutputModifier = renderer;
   this.accounts = {};
   if (this.executionContext.isVM()) {
-    this.addAccount('3cd7232cd6f3fc66a57a6bedc1a8ed6c228fff0a327e169c2bcc5e869ed49511');
-    this.addAccount('2ac6c190b09897cd8987869cc7b918cfea07ee82038d492abce033c75c1b1d0c');
-    this.addAccount('dae9801649ba2d95a21e688b56f77905e5667c44ce868ec83f82e838712a2c7a');
-    this.addAccount('d74aa6d18aa79a05f3473dd030a97d3305737cbc8337d940344345c1f6b72eea');
-    this.addAccount('71975fbf7fe448e004ac7ae54cad0a383c3906055a65468714156a07385e96ce');
+    this._addAccount('3cd7232cd6f3fc66a57a6bedc1a8ed6c228fff0a327e169c2bcc5e869ed49511');
+    this._addAccount('2ac6c190b09897cd8987869cc7b918cfea07ee82038d492abce033c75c1b1d0c');
+    this._addAccount('dae9801649ba2d95a21e688b56f77905e5667c44ce868ec83f82e838712a2c7a');
+    this._addAccount('d74aa6d18aa79a05f3473dd030a97d3305737cbc8337d940344345c1f6b72eea');
+    this._addAccount('71975fbf7fe448e004ac7ae54cad0a383c3906055a65468714156a07385e96ce');
   }
 };
 
@@ -58,9 +58,13 @@ UniversalDApp.prototype.newAccount = function () {
   this._addAccount(privateKey);
 };
 
-UniversalDApp.prototype.addAccount = function (privateKey, balance) {
+UniversalDApp.prototype._addAccount = function (privateKey, balance) {
   var self = this;
 
+  if (!self.executionContext.isVM()) {
+    throw new Error('_addAccount() cannot be called in non-VM mode');
+  }
+
   if (self.accounts) {
     privateKey = new Buffer(privateKey, 'hex');
     var address = ethJSUtil.privateToAddress(privateKey);