Add SvgAttrs (SVG attributes) according to MDN specifications 

Implementation of SVG attributes in order to generates svg attributes rathern than set in a style="" according to the MDN specs https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute.

I added the MDN comments for the first ones, I will continue if the PR is accepted :).
I tested it on small examples and it generates properly attributes for svg tags.
I upgraded the version number to 0.4.1-SNAPSHOT.