Poly line props

apply patch from Lukas Prediger to fix varios bugs with the polyline properties. #14 

See merge request !34

avoid expensive matrix update

profiling showed that update_matrices has a huge impact on performance. It's better to avoid updating the forward and backward transformations and computing them on the fly instead.

See merge request !30

License manager

Licensemanager checking systemtime

See merge request !29

This reverts commit 44f8338c.

Cpp11



See merge request !28

render polylines with colors

added draw modes for color per vertex/edge and implemented render code

issue #12 

See merge request !27

This reverts commit 166627f4.

It could also be inside a package.