Add ParameterConverter for ExamplesTable

To facilitate parsing of table parameters with tabular structure, it's useful to have a parameter converter that takes multi-line input and converts it to a ExamplesTable. This then allows users to match step such as:

Given the traders:

using a method with ExamplesTable parameter:

@Given("the traders: %tradersTable")
public void theTraders(ExamplesTable tradersTable) {
// use traders table to extract required data
}