Update CMake targets

VTK-m 2.0 changed the name of the exported targets to be in the vtkm namespace. Thus, library targets like vtkm_cont are now referenced like vtkm::cont.

Also did a quick pass through the build and install chapter to update features that were not properly documented.

examples/CMakeLists.txt

@@ -98,10 +98,10 @@ if (BUILD_EXAMPLES)
   create_test_sourcelist(test_src ${test_prog}.cxx ${example_src})
   add_executable(${test_prog} ${test_src})
   target_link_libraries(${test_prog}
-    vtkm_cont
-    vtkm_rendering
-    vtkm_cont_testing
-    vtkm_filter
+    vtkm::cont
+    vtkm::rendering
+    vtkm::cont_testing
+    vtkm::filter
     OpenGL::GL
     GLUT::GLUT
     Threads::Threads