- Adding initial support for Write functionality. Units & Transforms mostly. Enums still need work. Needs support for an IsDirty concept so that that every possible attribute isn't written.

- Refactored SvgElementFactory to use the new SvgElementAttribute to get available elements.

- Changed the ISvgStylable interface StrokeDashArray property to be of type SvgUnitCollection instead of     SvgUnit[] and updated SvgGraphicsElement to implement this change.

- Fixed #6324: SvgElement.PushTransforms and ViewBox - not necessarily related to ViewBox but every   element was 'resetting' the current graphics transform if the element contained it's own transform. This 
  was a very small fix for a large problem (SvgElement.PushTransforms Matrix transformMatrix = new   Matrix(); changed to Matrix transformMatrix = renderer.Transform; in order to inherit the current   transform.)
- Fixed #6344: Parsing document incorrectly parents elements when it encounters empty nodes which are   in a different namespace. Empty nodes are now ignored and current nodes are closed as required. We'll 
  see how this fix goes.
- Fixed #6381: Units in inches are incorrectly parsed as millimeters - problem was caused by some   copy/paste work.
- Graphics has been replaced by SvgRenderer. This is essentially a wrapper around graphics but will allow
  custom svg related properties in the future when needed.
- Removed ISvgRenderer: A concrete implementation is suitable.
- SvgElement.ElementName has been changed to non-virtual and is set by the parser instead of the   developer having to specify it when developing the class.
- Added more XML API documentation.

- SvgGradientStop offset values were not being confined to percentages (0.0-1.0 or %) so a ToPercentage() method has been added to SvgUnit which converts to a percentage unit. This method is called during the Offset property setter.
- SvgLinearGradientServer was incorrectly calculating the end point of the gradient.

- Fixed support for text-anchor="middle" and text-anchor="end" for <text/> elements.
- Added more XML API documentation
- Added x attribute and y attribute support to <use/> elements.