Revert "Working on making this export valid SVG documents."

Working on making this export valid SVG documents.

Scaling minx and miny of viewbox

SvgDocument as Write(XmlTextWriter); allowed elements to decide whether or
not they should be written. E.g. text elements should not be written
unless they have children.

Fixed many attribute enums. Now they will 1) output the proper case, 2) only output if non-null and non-default, 3) include more documentation, 4) are marked as Flags where appropriate.

Fix crash in GDI when empty rectangle

Parse Exponent stop-opacity

Stop crash on null or empty images
Deal with multiple spaces in Matrix

Added Icarrere suggestion

SvgDocument.Draw support different bitmap size as svg default size

Serialization Bug Fixes

More serialization bug fixes and better fallback for font definition
problems.

Added parameter to the SvgAttribute indicating whether the storage is
the _attribute dictionary.  If true, the output will only be serialized
only if the key is in the dictionary.  This structure is an alternate to
the SvgDefinitionDefaults class.

Revert "changed the default MatrixOrder to Prepend (instead of Append)"

changed the default MatrixOrder to Prepend (instead of Append)

fixed NullReferenceException when _styles is not set

fixed NullReferenceException in TryGetAttribute when _styles dictionary is not set to a valid reference

fixed invalid font size unit comparison

Revert "Performance Improvement"

Performance Improvement