D.Points: get rid of Control.Newtype
change Path projection function to a lens iso
Merge pull request #123 from nandykins/master

Version bump on lens
Updated Arrowhead.hs with diagrams-haddock
Added example diagrams to haddock
added annularWedge to TwoD.Arc
renamed r2
moved origin to center of circle
Merge branch 'master' into lens

Conflicts:
	src/Diagrams/CubicSpline.hs
	src/Diagrams/Points.hs
D.TwoD.Offset: update to use new pathTrails lens
hand-write pathTrails lens so we don't need TH
D.ThreeD.Types: update to use lens instead of newtype
remove newtype dependency
D.TwoD.Offset: need to import Control.Lens
Merge pull request #124 from diagrams/lens

Convert from newtype to lens
use lens for TransInv type
Export constructor of Path
Combinators to use Lens
exported lenses
Use new Envelope Iso