Ensure navigation titles are actually the title

Previously all navigation items and subclasses matched, thus the back button text could match.

Conflicts:
	gem/lib/frank-cucumber/core_frank_steps.rb
Move nav title to helper and add check method
Merge pull request #25 from joemasilotti/navigation-titles

Ensure navigation titles are actually the title
Merge branch 'joemasilotti-navigation-titles'