ADD: PHP Interface
ADD: yet untested TennisGame1H
ADD: PHPUnit Test Suite
ADD: PHPUnit Test Master (for Test-Data)
ADD: Unit Test for TennisGame1
FIX: ClassName
ignore IDE-Files (PHPStorm)
ADD: Test for third implementation
ADD: Tennis3 in PHP --
FIX: include => require_once
DEL: unnecessary statement  (PHP-ize)
ADD: TennisGame2 + PHPUnit Test
CHG: more PHP-Style