Add drawings and background images to slide layouts

[Brenneisen]

This pull request adds drawings and background images to slide layouts.

[Progi1984]

@Brenneisen Have you got a scenario for testing ? A Before/After ?

[Brenneisen]

Hi @Progi1984,

here is a simple scenario:

$presentation = new PhpPresentation;
$slideMaster = $presentation->getAllMasterSlides()[0];
$slideLayout = $slideMaster->getAllSlideLayouts()[0];

//Background Image
$background = new Image;
$background->setPath('./background.jpg');
$slideLayout->setBackground($background);

// Image
$shape = $slideLayout->createDrawingShape();
$shape->setPath('./logo.jpg');
$shape->setResizeProportional(true);
$shape->setWidth(130);
$shape->setOffsetX(25);
$shape->setOffsetY(670);

$writer = IOFactory::createWriter($presentation, 'PowerPoint2007');
$writer->save('./presentation.pptx');

The images are not displayed on the slide layout:

This pull request adds drawings and background images to the slide layouts.