Geometry: Added some extra checks in Triangle.
XFEM: Added safety check in EnrichmentItem.
Started to implement PrescribedGradientBCNeumann.
Fei2DQuadLin: Corrected computation of edge normal.
PrescribedGradientBCNeumann: account for cracks cutting the boundary.
Forgot two files in previous commit and fixed some errors.
Fixed merge conflicts in Geometry.
Fixed annoying warning when including Python.
Fixed more warnings and resolved problem from previous merge.
PrescribedGradientBCNeumann: Corrected scaling mistake and cleaned up
code.
DiscontinuousSegmentIntegrationRule: Cleaned up code.