SCRIPT70 Permission denied in selectors after iframe was submitted - Use native DOM over jQuery for iFrame HTML

Currently in IE9-10 there are issues with the jQuery library regarding failing selectors listed here [1]. Although it claims to be fixed, the bug has confirmed reports in the comments, the given test cases still fail in IE9-10, and it occurs in my use of ngUpload on IE9-10

Following the test case [4] listed on the jQuery bug report, I rewrote the portion of ngUpload that retrieves the html from the iFrame in cross browser native DOM [2]. The other benefit is that .html() is completely unnecessary since $.html() simply refers to innerHTML and performs unnecessary cross browser checks given the support for innerHTML [2, 3]. On older browsers like IE8 those cross browser checks can be a meaningful performance concern [3].

Happy to work with you on this if you can think of a better solution, but I would love to get this in ngUpload since the library has been fantastic besides this hitch. I only have one concern with this pull request that should confirm before merging, and I will comment inline on it.

[1] http://bugs.jquery.com/ticket/13936
[2] http://stackoverflow.com/questions/7570496/getting-the-document-object-of-an-iframe
[3] http://stackoverflow.com/questions/3563107/jquery-html-vs-innerhtml
[4]
```javascript
$(function () {
	$('input#button').click(function () {
		$('span');
		$('iframe').contents().find('form')[0].submit();
	});
});
```
------------
Test, Lint, and Uglification Report
```
codystebbins@Codys-MacBook-Pro ~/h/r/t/ngUpload> grunt jshint
Running "jshint:files" (jshint) task
>> 1 file lint free.

Done, without errors.
codystebbins@Codys-MacBook-Pro ~/h/r/t/ngUpload> grunt uglify
Running "uglify:ngUpload" (uglify) task
File "ng-upload.min.js" created.
Uncompressed size: 7679 bytes.
Compressed size: 530 bytes gzipped (2229 bytes minified).

Done, without errors.
codystebbins@Codys-MacBook-Pro ~/h/r/t/ngUpload> karma start
INFO [karma]: Karma server started at http://localhost:9876/
INFO [launcher]: Starting browser Chrome
INFO [Chrome 28.0 (Mac)]: Connected on socket id zAdItcvJoy7XoAfM2x4M
Chrome 28.0 (Mac): Executed 12 of 12 SUCCESS (1.141 secs / 0.124 secs)
```