mozilla/pdf.js — pull request #2781 by waddlesplash (2013-02-22 22:24:36+00:00)
Title: Ignore empty strings for text selection

They were causing double selection.

Test PDF: (just change ext. to .pdf and it'll work)
![test.pdf](https://f.cloud.github.com/assets/2175324/186933/969ed37a-7d3e-11e2-9918-e20f04d46c58.png)