Data tables

[ilyapuchka]

Resolves #41, resolves #146

This PR adds support for data tables. Examples of supported formats can be found in the doc comments for the new StepDefiner methods in NativeDataTable.swift and in ExampleFeatures tests. Both native and swift tests can use data tables. Examples are taken from a cucumber reference

The main difference of data tables and a step in an outline with values in examples is that the step in the outline will be invoked multiple times and each time will receive one element of example values, when with data tables it will be invoked once with all values in one collection.

Example:

Given("I add the following numbers:") {
    [1, 2, 3]
}

Given I have the following array:
| 1 |
| 2 |
| 3 |

[ianrhamilton]

How close are we to getting this feature merged?

[EfrainAndres]

Hello man,
the changes you made are in the master branch?

[kerrmarin]

👋 Sorry for the delay. Will review/test today.

[deanWombourne]

I'm loving this :)

The only issue I have is that in the step definitions (i.e. Tests/StepDefinitions.swift:194) the step needs to know whether it's been invoked from a Swift or a Native gherkin file (i.e. whether it should use DataTable or NativeDataTable as it's match type.

Is there any way of unifying these types somehow?

[ilyapuchka]

I think it won't be an issue in a reality as if one need to use the same step both with native and swift features with data tables (i.e. migrating from one format to another) they can extract code in this step into a reusable function or just call one step from another. But I think in most cases only one type of features is used.
I've improved docs around native data tables though.

[bbe02]

Hey @ilyapuchka, it will be nice if this PR can be merged after resolving the conflicts. Really looking forward to use the cucumber datatable facility.

[ianrhamilton]

Been a couple of years now - will this ever be merged?