Add ARFF support for reading data from

ARFF is a frequently used file format and EvoAl should support it.

At least @cplump votes for this issue.

assigned to @berber

added #7 (closed) as child task

added #8 (closed) as child task

Preparing commit to solve the first task: 1991ebda

mentioned in commit 75e1da01

Working on #8 (closed) in commit 6102892a

mentioned in commit 533682af

closed with commit e1317b7f