Added defs section to the SVG skeleton.
The definitions are not passed as maybe value.

I think this is more clear.
Added Options entry for the additional custom definitions.
Merge branch 'master' into font-embedding
Merge branch 'master' of github.com:diagrams/diagrams-svg into font-embedding
Merge branch 'master' into font-embedding
Merge branch 'master' into font-embedding
Merge branch 'master' into font-embedding
Merge branch 'master' into font-embedding
Removed setting standard attributes again, because it is allready called implicitly.
Added show instance for SVGOptions.
Show instance now prints in one line.
Merge pull request #38 from jbracker/font-embedding

Font embedding changes
Merge branch 'master' of github.com:diagrams/diagrams-svg