Now sound can be stopped with all the love of a well designed software in accord to UML standard

To allow that, function play(SoundCommand XX) was added to following classes

SixNodeElement
SixNodeElementRender
TransparentNodeElement
TransparentNodeElementRender

If sound is played by this way, it automaticaly stop when the block is breaked !
Ammmmmmmmmazing feactures ♫♪♫
Merge branch '1.7.2' of https://github.com/Dolu1990/ElectricalAge into 1.7.2