Investigate input layer parsing performance
For large input layer sets (250k+ break lines), simply loading the layer into the Lattice object takes unexpectedly long (this is based on the GUI progress indicator, it is possible that this is simply a status reporting issue, and that the bottle neck lies in a subsequent step instead).
This is related to #55 (closed), but even manually disabling all conformation in the source still causes this behaviour. The performance issue must either lie in the layer parsing itself, or in the generation of Triangle input files from the Lattice object.