If `SimMedTK_VTK_DIR` is defined, its value is used for `VTK_DIR`.
Otherwise, we ask CMake to find VTK and pass whatever it returns
from the superbuild to the SimMedTK build.

Documenting IO. Change name for IO delegates to match file name.

Capture by value in the IO delegator so that it remembers about the
delegate file name and IO pointer.

Fixing examples so they use the new IOs and renderer.

Add tests to IO. Move variables, types and implementation
of utility methods to IOMeshDelagates base class.

Commented out the VegaVoumetricMesh test until after I debug the meshIO.

until they are refactored.

Add reset function to base mash

in order to reset vertices to their original position.
Strip const from read function in the IOMeshDelegate and childs.
Move some utility functions to IOMeshDelegate.

corresponding simmedtk mesh structure.

Clean up as well.

This data mapper allows you to map external data into the
vtkDataArray.
This in turn allows you to interface with vtk without
repacking the simulatordata.

Clean up and implement a pimpl VtkRenderer to hide
redering implementation.

Replace core::StdVector3d with std::vector<core::Vec3d>

because eigen 3d vector array is aligned
by default so no special allocator is needed. See core::StdVector3d
for more details.

Remove IndiceArray from DataStructures

use std::vector instead and update methods accordingly.

See merge request !35

use std::vector instead and update methods accordingly.

Rename and restructure files and directories.

See merge request !34

and naming of the export targets.
Issue #27

Also renmamed many unseen sm* class names.

Add _USE_MATH_DEFINES to the windows compile definitions.

Document the Gitlab MR process...

... because there are some tricky bits (rough edges) where testing is concerned.

See merge request !32

Also fix instances where normalized was used wrongly.
Thank @tansel for spoting these.

Issue #27

Issue #27