Implementing toString() for figures

Doc/Sd1/inheritance.xml

P/Sd1/Figure/ToString/.gitignore

P/Sd1/Figure/ToString/pom.xml

...ing/src/main/java/de/hdm_stuttgart/mi/sd1/figure/App.java

...ain/java/de/hdm_stuttgart/mi/sd1/figure/model/Circle.java

...ain/java/de/hdm_stuttgart/mi/sd1/figure/model/Figure.java

.../java/de/hdm_stuttgart/mi/sd1/figure/model/Rectangle.java

...t/java/de/hdm_stuttgart/mi/sd1/figuretest/FigureTest.java

P/pom.xml