Debugger: Add memory views.

Add a separate memory view tool window available
from the context menus of:

Locals view:
   If the debugger provides size information, colors the
   areas of member variables for inspecting class layouts.

Registers view:
   Tracks the area pointed to by a register.

The view has a context menu allowing to open subviews
referenced by the pointer at the location using
the toolchain abi's word with/endianness.

Rubber-stamped-by: hjk

src/plugins/debugger/debuggerengine.h

@@ -82,6 +82,7 @@ class WatchHandler;
 class BreakpointParameters;
 class QmlCppEngine;
 class DebuggerToolTipContext;
+class MemoryViewWidget;
 
 struct WatchUpdateFlags
 {
@@ -157,6 +158,7 @@ public:
 
     virtual void watchPoint(const QPoint &);
     virtual void openMemoryView(quint64 addr);
+    virtual void addMemoryView(Internal::MemoryViewWidget *w);
     virtual void fetchMemory(Internal::MemoryAgent *, QObject *,
                              quint64 addr, quint64 length);
     virtual void changeMemory(Internal::MemoryAgent *, QObject *,