Debugger/WatchWindow: Add menu options to show pointed to addresses.

Change the WatchWindow handling to be based on quint64 addresses to
ensure proper function. Changed roles and added one role to the
watchmodel to obtain addresses and pointed-to addresses. Add some
fiddling to parse out addresses from debugger values.
Add menu options. Make sure only one watchpoint per address is added.

src/plugins/debugger/breakhandler.cpp

@@ -406,6 +406,16 @@ BreakpointData *BreakHandler::findBreakpointByNumber(int bpNumber) const
     return 0;
 }
 
+BreakpointData *BreakHandler::findWatchPointByAddress(const QByteArray &a) const
+{
+    for (int index = size() - 1; index >= 0; --index) {
+        BreakpointData *bd = at(index);
+        if (bd->type == BreakpointData::WatchpointType && bd->address == a)
+            return bd;
+    }
+    return 0;
+}
+
 void BreakHandler::saveBreakpoints()
 {
     QList<QVariant> list;