Merge branch 'feature/changelog-VC-support' into 'master'

[changelog] mention SIMD support

See merge request core/dune-istl!179

(cherry picked from commit 9471b3ec)

97d9c845 [changelog] mention SIMD support

CHANGELOG.md

@@ -5,3 +5,6 @@
 - `BDMatrix` and `BTDMatrix` now implement the `setSize` method, which allows to
   resize existing matrix objects.
 
+- The solver infrastructure was updated to support SIMD data types (see
+  current changes in `dune-common`). This allows to solve multiple systems
+  simultaniously using vectorization.