Line ending parsing is not cross platform

When following [Contributing to jQuery Foundation Web Sites](http://contribute.jquery.org/web-sites/) on Windows. grunt deploy fails with following message:
```
C:\code\jquery\contribute.jquery.org>grunt deploy
Running "clean:wordpress" (clean) task
Folder "dist/" contents removed.

Running "lint:grunt" (lint) task
Lint free.

Running "build-pages:all" (build-pages) task
Built 18 pages.

Running "build-resources:all" (build-resources) task
Built 5 resources.

Running "wordpress-validate" task
Validated 0 terms.
>> Error: dist/wordpress/posts/page/bug-reports.html is missing required data: t
itle
>> Error: dist/wordpress/posts/page/bug-reports.html is missing required data: t
itle
<WARN> Task "wordpress-validate" failed. Use --force to continue. </WARN>

Aborted due to warnings.
```
The cause is that grunt-jquery-content failed to parse out YAML headers because UNIX line ending is hard-coded.

The fix is to normalize file content by replacing platform specific line ending defined by os.EOL with '\n' before the YAML parsing.
Don't re-require `os`. Missing spaces. Double quotes.