Fix typo

…hat can become a string

It is convenient to be able to pass in URI objects to `visit`, but
these need to be coerced to a string before actual usage. Most of
visit's code paths would convert the incoming url to a string
as-needed. However, the path used when `always_include_port` is
enabled did not, causing an error where `URI.parse` would try to parse
an existing URI object.

This change consolidates the coercion to string at the entrypoint of
the method.

…_test

check correct version string for rspec composable

…ack::Lock

…EADME due to issue teamcapybara#1419

This test had a hardcoded values for the URI to visit which varies for different test cases. When these specs are integrated in custom driver's test suite like capybara-mechanize, it leads to failures.

This replaces teamcapybara#1227, which was rejected for changing the original purpose of the test. However, this patch only changes the hardcoding. It will allow phillbaker/capybara-mechanize#55 to proceed and bump it's compatibility to beyond capybara 2.1.