Project import location and vtk session
This branch has 2 main changes
- Adds smtk::project::Project::importLocation() so that users can reference their original input geometry at export time
- Implements an option to use vtk session to load models. This is a temporary workaround, put in place because vtk session captures the names assigned to side sets and element blocks in exodus files. If/when mesh session is updated to do the same thing, we should switch the default for this option off.