Swift Package Manager support

Added Swift Package Manager support (#22)

* Added Swift Package Manager support
* Update README

Try - catch for `replace` and `update`

Add try - catch to replace and update methods.

Try - catch support

Add try - catch support in tests.

Custom HTTP created 201 response body

Add support for custom HTTP created 201 response body

Inject custom API mocks on app launch

In order to use custom API response mocks (with special data) we used

start(using: AppConfiguration())

app.replaceValues(
    of: [
        "result": "NOT_AUTHENTICATED"
    ],
    in: Stub.Authentication.success
)

But API mocked responses were replaced only after next refresh/API call. So as a workaround we had to do additional UI actions like pull to refresh, closing and opening screens again and so on, just to get that API endpoint called again.

This PR adds nicer way to do that by introducing initiationClosure param to start(using:)
So, now there is a way to do:

start(using: Configuration()) { app in
    app.replaceValues(
        of: [
            "result": "NOT_AUTHENTICATED"
        ],
        in: Stub.Authentication.success
    )
}
.loginStep.authenticationStatusIsVisible()
.loginStep.authenticationStatusIs(equal: "NOT_AUTHENTICATED")

Using this closure we get our custom replaced API mocks right after UI Tests launches the app.

To better illustrate that, I have updated example app with few examples.

0.13: Merge pull request #16 from treatwell/Add-support-for-HTTP-201-created

Add created http status code

0.12: Merge pull request #15 from antranapp/change_protocol

Expose start function to be used in tests for restart scenario.

Add scrollView swipe helpers

Merge pull request #13 from treatwell/Add-XCUIelement-find-method-

Add XCUIElement find method

Tableview load checking

Add tableview loaded checking method

Check element if it exists on screen

Merge pull request #10 from treatwell/Add-check-for-is-element-hittab…

…le-to-swipeUp

Added a check for element.isHittable to swipeUp func to ensure…