The electron-context-menu package uses the context-menu event emitted by WebContents (API added in Electron 1.0.2) to add a general context menu supporting generic actions (e.g. cut/copy/paste) that can be customized. This change replaces the existing context menu, which relies on adding an event listener in preload.js, with one built using the new package.
Test case: open nativefier on
```html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Test</title>
</head>
<body>
<a href="https://google.com/">Google</a>
<br>
<a href="https://google.com/"><span>Google, in span</span></a>
</body>
</html>
```
* **Expected**: both links open in default browser
* **Actual under nativefier 7.0.1**: Nothing happens when clicking the second link in which the `<a>` contains a `<span>`
