Dependency updates

Upgrade dependencies thanks to the fast pace and deprecation policies within the 
ruby community, want to keep reasonably current with our dependencies.

capybara has some good changes. It fails if there are ambiguous targets for `click_link`.
I've changed to use `first(:link, "link name").click` in parts, or use `within` to be
more explicit but there was one example where we had 2 lenders rather than one and we
might want to look more closely at why that is.

`has_css` has changed to take `text` key rather than `value`

`fill_in` now requires exact text rather than prefix matching.

`select` doesn't match against the `value` attribute of the `option` element, so I've had to
make a slightly less readable change for now.