* use element applies referenced viewBox scaling
* created FontManager

- prevents crash, fixes #223

- XML is case-sensitive, so some viewers / browsers choke on incorrect case
- fixes #272

- fixes W3C example painting-marker-04-f.svg

- transformations in the marker drawing element have been ignored
- fixes #215

- fixed stroke and fill color (taken from marker or from included path)
- added missing scaling for markerUnits="strokeWidth"
- fixed initial value of "orient" to be "0"
- fixes 2 of the W3C tests

- partly fixes respective W3C examples

- handle markers on paths with successive equal points
 (fixing drawing of __issue-345-01.svg)

- this kind of IDs caused a crash before
- fixes #345

* Repair calculate a percentage value
* Add percentage size tests

- fixes #342

- fixes #405

- fixes #331

- fixes #323 (caused crash)

- set correct default for fill/stroke unset color
- fixes #398

- fixes #191

the recently introduced optional size parameter is causing incompatibilities with our C++ application.

Unit Calculation: add spaces between operatores, remove obsolete default branch in switch statement.
bug fix #338

Fix issue with percentage unit in "stroke-width", now taken from the viewbox width/height normalised diagonale for x/y elements e.g. circle
Test images and svg under #338

- fixes #58

- could break the functionality if writing is not possible in root
- see #372

Fix Issue #385, using TextBounds.Width rather than path bounds to ensure proper font alignment for "middle" and "end" - see also "text-align-03-b"

- added "stroke-dashoffset" support
- added "painting-stroke-04-t" to "PassingTests" (csv/txt)
- fixes #388 

- see #384

- added image broken by regression to tests (__Flag_of_the_United_States)
- added some passing issue specific tests to image comparison tests

See ExCSS pull request #62: https://github.com/TylerBrinks/ExCSS/pull/62

- found by @Seairth
- fixes #108

- ignore elements with recursive references
- fixes stack overflow for test image struct-use-12-f.svg

- originally provided by @ssteiger in #316

- fixes TestPrivateFront unit test (threw exception because the image
  had zero size, as the only element is a "use" element)