Visual Studio Native Visualizations for constructors and methods

With this change, the class

  struct A {
    A(int _i);
    ~A();
    int foo(double d);
    double bar(A *a) { return 1.3; }
  };

appears in the VS2015 Locals Window as

D              0x02dbb378 struct A
|- DeclKind    CXXRecord
|- Members
 |- [0]        implicit struct A
 |- [1]        Constructor {A(int _i)}
 |- [2]        Destructor {~A()}
 |- [3]        Method {int foo(double d)}
 |- [4]        Method {double bar(struct A *)}
|- [Raw View]  /* Other stuff */

Note that these changes only benefit VS2015 as
VS2013 does not have views and only displays the
struct name "A", but the change does no apparent
harm in VS2013, so is still a win.

llvm-svn: 264020