Replace all DOMMatrix args with DOMMatrixInit, with the appropriate algorithm modifications

[sideshowbarker]

See #34 (comment)

[domenic]

This would notably allow authors to pass in object literals, e.g. { left: 0, top: 10, bottom: 20, right: 30 }, instead of having to create new DOMMatrix instances. It's generally good practice to allow dictionary inputs in cases like these, and is the reason DOMMatrixInit was invented.

[annevk]

#34 also left "SVG" in place just prior to "Geometry Interfaces Module". It seems that was not properly cleaned up.