[fixed] 'componentClass' property type is 'elementType' now

And it is not 'isRequired' now if a default value
in getDefaultProps() for it is provided.

src/Button.js

@@ -1,6 +1,7 @@
 import React from 'react';
 import classNames from 'classnames';
 import BootstrapMixin from './BootstrapMixin';
+import CustomPropTypes from './utils/CustomPropTypes';
 
 const Button = React.createClass({
   mixins: [BootstrapMixin],
@@ -11,7 +12,7 @@ const Button = React.createClass({
     block: React.PropTypes.bool,
     navItem: React.PropTypes.bool,
     navDropdown: React.PropTypes.bool,
-    componentClass: React.PropTypes.node,
+    componentClass: CustomPropTypes.elementType,
     href: React.PropTypes.string,
     target: React.PropTypes.string
   },

src/Col.js

@@ -1,6 +1,7 @@
 import React from 'react';
 import classNames from 'classnames';
 import styleMaps from './styleMaps';
+import CustomPropTypes from './utils/CustomPropTypes';
 
 const Col = React.createClass({
   propTypes: {
@@ -20,7 +21,7 @@ const Col = React.createClass({
     smPull: React.PropTypes.number,
     mdPull: React.PropTypes.number,
     lgPull: React.PropTypes.number,
-    componentClass: React.PropTypes.node.isRequired
+    componentClass: CustomPropTypes.elementType
   },
 
   getDefaultProps() {

src/Grid.js

@@ -1,10 +1,11 @@
 import React from 'react';
 import classNames from 'classnames';
+import CustomPropTypes from './utils/CustomPropTypes';
 
 const Grid = React.createClass({
   propTypes: {
     fluid: React.PropTypes.bool,
-    componentClass: React.PropTypes.node.isRequired
+    componentClass: CustomPropTypes.elementType
   },
 
   getDefaultProps() {

src/Jumbotron.js

@@ -1,9 +1,10 @@
 import React from 'react';
 import classNames from 'classnames';
+import CustomPropTypes from './utils/CustomPropTypes';
 
 const Jumbotron = React.createClass({
   propTypes: {
-    componentClass: React.PropTypes.any.isRequired
+    componentClass: CustomPropTypes.elementType
   },
 
   getDefaultProps() {

src/Navbar.js

@@ -4,6 +4,7 @@ import classNames from 'classnames';
 
 import ValidComponentChildren from './utils/ValidComponentChildren';
 import createChainedFunction from './utils/createChainedFunction';
+import CustomPropTypes from './utils/CustomPropTypes';
 
 const Navbar = React.createClass({
   mixins: [BootstrapMixin],
@@ -15,7 +16,7 @@ const Navbar = React.createClass({
     inverse: React.PropTypes.bool,
     fluid: React.PropTypes.bool,
     role: React.PropTypes.string,
-    componentClass: React.PropTypes.node.isRequired,
+    componentClass: CustomPropTypes.elementType,
     brand: React.PropTypes.node,
     toggleButton: React.PropTypes.node,
     toggleNavKey: React.PropTypes.oneOfType([

src/Row.js

@@ -1,9 +1,10 @@
 import React from 'react';
 import classNames from 'classnames';
+import CustomPropTypes from './utils/CustomPropTypes';
 
 const Row = React.createClass({
   propTypes: {
-    componentClass: React.PropTypes.node.isRequired
+    componentClass: CustomPropTypes.elementType
   },
 
   getDefaultProps() {