fix styles for void, fix tests for void rendering

lib/components/void.js

@@ -21,6 +21,10 @@ class Void extends React.Component {
     style: React.PropTypes.object
   };
 
+  static defaultProps = {
+    style: {}
+  }
+
   shouldComponentUpdate = (props) => {
     return (
       props.node != this.props.node ||
@@ -34,20 +38,18 @@ class Void extends React.Component {
     const Tag = node.kind == 'block' ? 'div' : 'span'
 
     // Make the outer wrapper relative, so the spacer can overlay it.
-    const relative = {
+    const styles = {
+      ...style,
       position: 'relative'
     }
 
     return (
-      <Tag
-        contentEditable={false}
-        style={relative}
-      >
+      <Tag contentEditable={false}>
         <Tag
           contentEditable
           suppressContentEditableWarning
           className={className}
-          style={style}
+          style={styles}
         >
           {this.renderSpacer()}
           <Tag contentEditable={false}>{children}</Tag>

test/rendering/fixtures/custom-block-void/index.js

@@ -1,8 +1,13 @@
 
+import { Void } from '../../../..'
 import React from 'react'
 
 function Image(props) {
-  return <img src={props.node.data.get('src')} />
+  return (
+    <Void {...props}>
+      <img src={props.node.data.get('src')} />
+    </Void>
+  )
 }
 
 export function renderNode(node) {

test/rendering/fixtures/custom-block-void/output.html

@@ -1,6 +1,7 @@
 
 <div contenteditable="true">
-  <div style="position:relative;">
+  <div contenteditable="false">
+    <div contenteditable="true" style="position:relative;">
       <span style="position:absolute;top:0px;right:0px;bottom:0px;left:0px;text-indent:-9999px;">
         <span>
           <br>
@@ -11,3 +12,4 @@
       </div>
     </div>
   </div>
+</div>

test/rendering/index.js

@@ -54,7 +54,7 @@ function clean(html) {
     $(el).removeAttr('data-offset-key')
   })
 
-  $('[contenteditable]').removeAttr('style')
+  $.root().children().removeAttr('style')
 
   return $.html()
 }