* If an exception is raised in the Ruby process, it's possible for Reset
to be sent to the server while the previous command is still running.
This ensures that pending commands are stopped when handling Reset.
* Retain backwards compatibility with legacy capybara-webkit API.
* Confirm dialogs are accepted by default; dialogs are dismissed.
* Legacy API overrides the default action, and does not raise errors
for unexpected modals.
* When WEBKIT_SERVER_START_TIMEOUT was reached, @port would get set to
nil. If execution of the SERVER_PROCESS returned immediately, @port
would get set to 0. This lead to odd cross-platform behavior in
#connect, which would try to connect to a nonsense port.
* Test Capybara 2.2 and 2.3 compatibility on all platforms.
* Drop support for Capybara 2.0.
* Only test Qt 5 on 1.9.3. The C implementation is the same for all Ruby
versions, so there's no need to test against all platforms.