Build paths for glyph accents when drawing text as curves

This PR fixes (taken from the list at http://bthorben.github.io/pdfRepo/#crashed):
* http://www.senac.br/media/1181/correio_709.pdf
* http://www.mediadesign.de/sites/default/files/m2-_vom_2013-01-11_seite_03.pdf

*Note:* even though this PR fixes the error that prevents the files from rendering completely, there is still a slight issue with the second file. At the bottom of the page, the dots above the `u` are placed too far to the left. However that is probably better to handle in a follow-up, since it's most likely an issue with the font data in that particular file.
![pdfjs](https://cloud.githubusercontent.com/assets/2692120/2870747/bc7fe462-d2dd-11e3-92d8-9a41751e510a.png)