allows the model to take empty tables given by cucumber

when an empty table is passed in and update is called, the hash passed into the model is a "" => nil. This change makes the model remove empty entries that are just empty strings.
updates gemspec to use the newest selenium-webdriver with a version bump
Merge remote-tracking branch 'origin/master'

Conflicts:
	lib/watirmark/version.rb
Implements statistic gathering