add pattern

[hakrueger]

• no build files included in this commit
• should work on shapes, text, charts, and tables

Example usage: slide.addShape(pptx.shapes.RECTANGLE, { x: 5.1, y: 6, w: 3.0, h: 1, fill = { type: 'patternFill', color: '000000', bgColor: 'FFFFFF', prst: 'openDmnd' } });