Some of the Object::equals now are const correct.

There's more to do.

Why make this const-correct, instead of ditch it?  Because whatever
I replace it with has to be ready for const correctness.

dw/iterator.cc

@@ -47,15 +47,17 @@ Iterator::~Iterator()
 {
 }
 
-bool Iterator::equals (Object *other)
+bool
+Iterator::equals( const Object *const other ) const
 {
-   Iterator *otherIt = (Iterator*)other;
+   Iterator *const otherIt = const_cast< Iterator * >( dynamic_cast< const Iterator * >( other ) );
    return
       this == otherIt ||
-      (getWidget() == otherIt->getWidget() && compareTo(otherIt) == 0);
+      (const_cast< Iterator * >( this )->getWidget() == otherIt->getWidget() && const_cast< Iterator * >( this )->compareTo(otherIt) == 0);
 }
 
-void Iterator::intoStringBuffer(misc::StringBuffer *sb)
+void
+Iterator::intoStringBuffer(misc::StringBuffer *sb) const
 {
    sb->append ("{ widget = ");
    //widget->intoStringBuffer (sb);
@@ -68,7 +70,7 @@ void Iterator::intoStringBuffer(misc::StringBuffer *sb)
    Content::maskIntoStringBuffer (mask, sb);
 
    sb->append (", content = ");
-   Content::intoStringBuffer (&content, sb);
+   Content::intoStringBuffer (const_cast< Content * >( &content ), sb);
 
    sb->append (" }");
 }

dw/iterator.hh

@@ -30,8 +30,8 @@ private:
    Content::Type mask;
 
 public:
-   bool equals (Object *other);
-   void intoStringBuffer(lout::misc::StringBuffer *sb);
+   bool equals (const Object *other) const override;
+   void intoStringBuffer(lout::misc::StringBuffer *sb) const override;
 
    inline Widget *getWidget () { return widget; }
    inline Content *getContent () { return &content; }

dw/style.cc

@@ -155,7 +155,7 @@ bool StyleAttrs::sizeDiffs (StyleAttrs *otherStyle)
    return false;
 }
 
-bool StyleAttrs::equals (object::Object *other) {
+bool StyleAttrs::equals (const object::Object *other) const {
    StyleAttrs *otherAttrs = (StyleAttrs *) other;
 
    return this == otherAttrs ||
@@ -398,7 +398,7 @@ void Style::copyAttrs (StyleAttrs *attrs)
 
 // ----------------------------------------------------------------------
 
-bool FontAttrs::equals(object::Object *other)
+bool FontAttrs::equals(const object::Object *other) const
 {
    FontAttrs *otherAttrs = (FontAttrs*)other;
    return
@@ -456,7 +456,7 @@ bool Font::exists (Layout *layout, const char *name)
 
 // ----------------------------------------------------------------------
 
-bool ColorAttrs::equals(object::Object *other)
+bool ColorAttrs::equals(const object::Object *other) const
 {
    ColorAttrs *oc = (ColorAttrs*)other;
    return this == oc || (color == oc->color);

dw/style.hh

@@ -508,7 +508,7 @@ public:
    int top, right, bottom, left;
 
    inline void setVal(int val) { top = right = bottom = left = val; }
-   inline bool equals (Box *other) {
+   inline bool equals (const Box *other) const {
       return top == other->top &&
          right == other->right &&
          bottom == other->bottom &&
@@ -603,7 +603,7 @@ public:
    inline bool hasBackground ()
    { return backgroundColor != NULL || backgroundImage != NULL; }
 
-   bool equals (lout::object::Object *other);
+   bool equals (const lout::object::Object *other) const override;
    int hashValue ();
 };
 
@@ -688,7 +688,7 @@ public:
    FontVariant fontVariant;
    FontStyle style;
 
-   bool equals(lout::object::Object *other);
+   bool equals(const lout::object::Object *other) const override;
    int hashValue();
 };
 
@@ -742,7 +742,7 @@ public:
 
    inline int getColor () { return color; }
 
-   bool equals(lout::object::Object *other);
+   bool equals(const lout::object::Object *other) const override;
    int hashValue();
 };