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
use getLength() to calculate a segment length
pass a Point object to findTriangle(). add documment
changed a constructor to take std::array. allow N_VARS=0. use std::inner_product
remove a default value for default_value
rename to LinearInterpolationOnSurface. remove a default value. documents interpolation.
add comments
fix compiling errors in test
fix a bug that zero distance was not accepted
[GeoLib::Polyline] Compute values only when needed.
Merge pull request #30 from TomFischer/add-function-of-space

A very small improvement
Merge pull request #369 from norihiro-w/add-function-of-space

Initial implementation of spatial functions