Hotfix to give phantomjs a bit more time to start with GhostDriverUac.

This introduces a bit of delay for all users of the GhostDriverUac. In future,
we will probably want a more intelligent mechanism to wait for phantomjs process to fully
initialize before proceeding.
Merge pull request #276 from sethmcl/master

Hotfix to give phantomjs a bit more time to start with GhostDriverUac.