This allows positioning a child SVG relative to its parent SVG.
Note: These have been implemented as CSS properties as in SVG 2, these
are geometry properties that can be used in CSS (see
https://www.w3.org/TR/SVG/geometry.html), but there is not much browser
support for this. It is nicer to implement than the ad-hoc SVG
attribute parsing though, so I feel it may make sense to port the rest
of the attributes specified here (which should fix some issues with
viewport relative sizes).
Print out the value of each property in the computed-style of the body
element. This is by no means a thorough test that we're serializing
every property's value correctly in every configuration, (and in fact,
some are definitely wrong,) but it does give us a nice baseline.
