[rttopo-dev] rtt_AddLineNoFace available in master branch

[Sandro Santilli]

I've made available a new function: rtt_AddLineNoFace.
The function allows adding an arbitrary line to an existing
topology, noding it as appropriate with existing linework,
but NOT checking for new faces being generated.

It's been tested for incremental lines addition starting
from an empty topology and it works fine. The datastore
is passed edge records with left_face/right_face valued -1
to signify "unknown".

Tests welcome.

--strk;