Add a constructor to IceModelVec2S.

This one allocates memory. (Unlike the default constructor, which I
need to remove at some point.)

So far this just makes it possible to allocate IceModelVec2S in one
step instead of two.

src/base/util/iceModelVec.hh

@@ -394,6 +394,8 @@ class IceModelVec2S : public IceModelVec2 {
   friend class IceModelVec2Stag;
 public:
   IceModelVec2S();
+  IceModelVec2S(IceGrid::ConstPtr grid, const std::string &name,
+                IceModelVecKind ghostedp, int width = 1);
 
   typedef std::shared_ptr<IceModelVec2S> Ptr;
   typedef std::shared_ptr<const IceModelVec2S> ConstPtr;

src/base/util/iceModelVec2.cc

@@ -77,6 +77,14 @@ IceModelVec2S::IceModelVec2S() {
   m_begin_end_access_use_dof = false;
 }
 
+IceModelVec2S::IceModelVec2S(IceGrid::ConstPtr grid, const std::string &name,
+                             IceModelVecKind ghostedp, int width) {
+  m_begin_end_access_use_dof = false;
+
+  create(grid, name, ghostedp, width);
+}
+
+
 IceModelVec2Stag::IceModelVec2Stag()
   : IceModelVec2() {
   m_dof = 2;