Adding ArrayHandleVirtual, and VariantArrayHandle, Removing DynamicArrayHandle

This is one small step for virtuals, one large leap for VTK-m.

This is no where near completion, but should allow for compilation of vtkm_cont and all tests in vtkm/cont/.

Below is currently all the known issues/tasks that need to be resolved. As I update this work I will be adding new tasks, checking off work.

Major Tasks:

• Redesign Filter Policies for virtuals
• Correct dynamic_cast visibility issues showing on OSX.

Documentation Tasks:

• Add Changelog for ArrayHandleVirtual
• Add Changelog for ArrayHandleVariant
• Update User's Guide

Conversion Tasks:

• Convert over IO
• Convert over Rendering
• Convert over Filters
• Convert over Worklets
• Convert over Benchmarks
• Convert over Examples
• Convert over per backend unit tests
• Convert over Serialization to support ArrayHandleVirtual

Design Tasks:

• Redesign ArrayRangeCompute to handle ArrayHandleVirtual.
• Re-Activate fast paths for Worklets executing on UniformPointCoordinates.
• Get ArrayHandleZip to be stored by ArrayHandleVariant.

Minor Design Tasks:

• Investigate which Fancy ArrayHandles should be moved over to always use ArrayHandleVirtual as the parent class

Minor Coding Tasks:

• Implement Shrink on StorageVirtual
• Implement Allocate on StorageVirtual
• Implement PrepareForInPlace on StorageVirtual
• Mark Get and Set methods as noexcept on ArrayPortalVirtual, ArrayPortalWrapper, ArrayPortalRef
• Add Move (&&) Constructors and Assignment Operator ArrayPortalVirtual, ArrayPortalWrapper, ArrayPortalRef
• Add Move (&&) Constructors and Assignment Operators for ArrayHandleVariant, Field, CoordinateSystem, and DataSet