Log Message:
Update ruby-capybara to 2.14.0.

pkgsrc change: depends on ruby-rack16 instead of ruby-rack.

# Version 2.14.0

Release date: 2017-05-01

### Added

* "threadsafe" mode that allows per-session configuration
* `:type` filter added to the `:fillable_field` selector
* Proxy methods when using RSpec for `all`/`within` that call either the
  Capybara::DSL or RSpec matchers depending on arguments passed
* Support for the new errors in selenium-webdriver 3.4

### Fixed

* Element#inspect doesn't raise an error on obsolete elements
* Setting a contenteditable element with Selenium and Chrome 59
* Workaround a hang while setting the window size when using geckodriver 0.16
  and Firefox 53
* Clicking on url with a blank href goes to the current url when using the
  RackTest driver