Added exporter for __PHP_Incomplete_Class

More readable variant of output for __PHP_Incomplete_Class.

Before:
![php-incomplete-class-old](https://cloud.githubusercontent.com/assets/144181/4295985/19c3da3e-3df0-11e4-87ef-dd759ef2d9d1.png)

After:
![php-incomplete-class](https://cloud.githubusercontent.com/assets/144181/4295957/c3e565ec-3def-11e4-9f79-06da85182af8.png)