updated layout settings for GMSH preferences dialog
resized some dialogs
extract rotate() from EarClippingTriangulation
add findTriangle() in Surface class
add getDistanceAlongPolyline() to Polyline. The code is extracted from MeshNodesAlongPolyline.
add Mesh object as a member variable of MeshNodesAlongPolyline and MeshNodesAlongSurface. Use getDistanceAlongPolyline() in Polyline.
add LinearFunction in MathLib
add SpatialFunction in NumLib/Function
add a linear function of space
add linear interpolation along polyline and surface
add tests for spatial functions