use lens for TransInv type
Export constructor of Path
Combinators to use Lens
exported lenses
Use new Envelope Iso
travis: build against lens branch of core
fixed export
Merge branch 'lens' of https://github.com/diagrams/diagrams-lib into lens
Segments to us Lens
Trail to use Lens
Parametric.Adjust to use Lens
New Iso for P3, export r3Iso, p3Iso
Control.Lens lenses for camera lenses
remove a typo
Trail  changed Lens to Iso
Finished lensifying Segement and Trail
Lensified TwoD.Image
Lenses for ScaleInv
Changes to Segment and Trail
Lensify TwoD.Types and TwoD.Vector