[pt] Remove Zero-width space character (U+200B)

Remove Zero-width space character (U+200B) from PT documents.
It was a cause of this invisible character fails to PDF conversion.

It is not visible on GitHub, I want you to look at the capture below.

![cap](https://f.cloud.github.com/assets/10488/1860127/c8558f60-77ae-11e3-97f8-d447b654345c.png)


Relation: #1001