added renderDtree
progress on styles, need to fix transforms
transform working - need to optimize in DTree, SVG upside down
fixed problem with inserting needless identity transforms
progress towards freeze
diagrams right side up, transformations after freeze incorrect
all test cases working - except for clipping
fixed problem with line width
pushed handling of transforms down to Compile.hs
removed renderDTree
removed case for RUnfrozen Nodes
no longer any need to pass frozen transformations to renderSvgWithClipping
Uses experimental Backend Typeclass implementation
uses revised -core/backend
use toRTree from D.Core.Compile
Merge branch 'master' into optimize

Conflicts:
	diagrams-svg.cabal
	src/Diagrams/Backend/SVG.hs