Create data tables for arbitrary arguments

[janschaefer]

Currently JGiven creates data tables if parameters of cases are different. However, if arguments differ that are no parameters, data tables are not generated.
Example:

Case 1: a = 5
Given some 5
When foo 6
Then bar

Case 2: a = 7
Given some 7
When foo 8
Then bar

As the argument of foo is not a parameter, no data table is generated.

Desired output:

Given some <a>
When foo <b>
Then bar

|  a  |  b  |
|  5  |  6  |
|  7  |  8  |

The name of the variable should be derived from the variable name of the called method