ENH: Expose a binary parameter to meshwrite function
STYLE: MeshFileWriter: ivars initialized in header, remove default ctor
STYLE: Replace `GetVnlVector().magnitude()` calls with `GetNorm()`
DOC: Add the term "magnitude" to `Vector::GetNorm()` documentation
ENH: Add `Vector.NormEqualsVnlVectorMagnitude` GTest unit test
ENH: Test ImageBase, ImageRegion `GetImageDimension()` at compile-time
ENH: Declare `GetImageDimension()` member functions constexpr
BUG: Fix ImageToRectilinearFEM tests arg checks