Reviewed (and tweaked a little) by Maciej.
        
        - shrank the size of JSObject by 8 bytes and made the corresponding reduction to the cell size, resulting
        in a 1.2% speed improvement on JS iBench (and probably overall memory savings).

        This was done by removing _scope and _internalValue data members
        from JSObject and moving them only to the subclasses that actually
        make use of them.
        
        * kjs/object.cpp: 
        (KJS::JSObject::mark): No need to mark scope or internal value here.
        * kjs/object.h:
        (KJS::JSObject::JSObject): Don't initialize them.
        * kjs/JSWrapperObject.cpp: Added. New base class for object types that
        wrap primitive values (Number, String, Boolean, Date).
        (KJS::JSWrapperObject::mark): 
        * kjs/JSWrapperObject.h: Added.
        (KJS::JSWrapperObject::JSWrapperObject):
        (KJS::JSWrapperObject::internalValue):
        (KJS::JSWrapperObject::setInternalValue):
        * kjs/array_object.cpp:
        (ArrayPrototype::ArrayPrototype): Don't set useless internal value.
        * kjs/bool_object.cpp:
        (BooleanInstance::BooleanInstance): Inherit from JSWrapperObject.
        (BooleanProtoFunc::callAsFunction): Fixed to account for fact that not all
        JSObjects have an internal value.
        (BooleanObjectImp::construct): ditto.
        * kjs/bool_object.h:
        * kjs/collector.cpp: Lowered cell size to 48.
        (KJS::Collector::allocate): meaningless whitespace change
        * kjs/date_object.cpp:
        (KJS::DateInstance::DateInstance): Inherit from JSWrapperObject.
        (KJS::DateProtoFunc::callAsFunction): adjusted for move of internalValue
        (KJS::DateObjectImp::construct): ditto
        * kjs/date_object.h:
        * kjs/error_object.cpp:
        (ErrorPrototype::ErrorPrototype): don't set internal value
        * kjs/function.cpp: move _scope and related handling here
        (KJS::FunctionImp::mark): mark scope
        * kjs/function.h:
        (KJS::FunctionImp::scope): moved here from JSObject
        (KJS::FunctionImp::setScope): ditto
        * kjs/number_object.cpp:
        (NumberInstance::NumberInstance): inherit from JSWrapperObject
        (NumberProtoFunc::callAsFunction): adjusted
        (NumberObjectImp::construct): adjusted
        * kjs/number_object.h: shring RegExp-related objects a little
        * kjs/regexp_object.cpp:
        (RegExpPrototype::RegExpPrototype): Adjust for size tweaks
        (RegExpObjectImp::RegExpObjectImp): ditto
        * kjs/regexp_object.h:
        * kjs/string_object.cpp:
        (StringInstance::StringInstance): inherit from JSWrapperObject
        (StringProtoFunc::callAsFunction): adjusted
        * kjs/string_object.h:
        * JavaScriptCore.exp: Exported new methods as needed.
        * JavaScriptCore.xcodeproj/project.pbxproj: Added new files to build.

WebCore:

        Reviewed (and tweaked a little) by Maciej.
        
        - shrank the size of JSObject by 8 bytes and made the corresponding reduction to the cell size, resulting
        in a 1.2% speed improvement on JS iBench (and probably overall memory savings).

        The WebCore part of this is to expect only FunctionImp to have a scope, not all JSObjects.
        
        * bindings/js/kjs_events.cpp:
        (KJS::JSLazyEventListener::parseCode):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@15846 268f45cc-cd09-0410-ab3c-d52691b4dbfc