replacing all occurances of locator with selector
added #add_checkers_and_waiters and refactored to use it
renamed #element_names to #mapped_items
added details to history
removing whitespace
updating the todo list
refactoring how mapped items are added to the class - much cleaner now
added #build_checker_or_waiter and refactored to use it
Updating a few typos in readme
Merge pull request #8 from nathanbain/master

Fixing a few README typos
limiting capybara and rspec version dependency, updating site_prism version
allow creation of anonymous sections via block to element