Rename vec_access() and vec_size() methods

This commit renames the vec_access() and vec_size() methods to match the ones in the DenseVector facade class, that is operator[]() and size().

Closes #3 (closed)

dune/common/densevector.hh

@@ -284,18 +284,18 @@ namespace Dune {
//! random access
value_type & operator[] (size_type i)
{
-      return asImp().vec_access(i);
+      return asImp()[i];
}
const value_type & operator[] (size_type i) const
{
-      return asImp().vec_access(i);
+      return asImp()[i];
}
//! size method
size_type size() const
{
-      return asImp().vec_size();
+      return asImp().size();
}
//! Iterator class for sequential access