remove nonCompliant argument from deriveChild, fix travis file

.travis.yml

@@ -1,9 +1,9 @@
 language: node_js
 sudo: false
 node_js:
-  '0.10'
+- '0.10'
-  '0.12'
+- '0.12'
-  '2.0.0'
+- '2.0.0'
 - '4'
 before_install:
   - npm install -g bower

lib/hdprivatekey.js

@@ -184,14 +184,12 @@ HDPrivateKey.prototype.derive = function(arg, hardened) {
  *
  * @param {string|number} arg
  * @param {boolean?} hardened
- * @param {boolean?} nonCompliant - This should not be used and only for backwards compatibility
- *
  */
-HDPrivateKey.prototype.deriveChild = function(arg, hardened, nonCompliant) {
+HDPrivateKey.prototype.deriveChild = function(arg, hardened) {
   if (_.isNumber(arg)) {
-    return this._deriveWithNumber(arg, hardened, nonCompliant);
+    return this._deriveWithNumber(arg, hardened);
   } else if (_.isString(arg)) {
-    return this._deriveFromString(arg, nonCompliant);
+    return this._deriveFromString(arg);
   } else {
     throw new hdErrors.InvalidDerivationArgument(arg);
   }
@@ -214,8 +212,13 @@ HDPrivateKey.prototype.deriveChild = function(arg, hardened, nonCompliant) {
  * @param {boolean?} hardened
  */
 HDPrivateKey.prototype.deriveNonCompliantChild = function(arg, hardened) {
-  var derived = this.deriveChild(arg, hardened, true);
+  if (_.isNumber(arg)) {
-  return derived;
+    return this._deriveWithNumber(arg, hardened, true);
+  } else if (_.isString(arg)) {
+    return this._deriveFromString(arg, true);
+  } else {
+    throw new hdErrors.InvalidDerivationArgument(arg);
+  }
 };
 
 HDPrivateKey.prototype._deriveWithNumber = function(index, hardened, nonCompliant) {