* kjs/property_map.h: Rewrite to use a hash table.
        * kjs/property_map.cpp: Ditto.

        * kjs/string_object.h:
        * kjs/string_object.cpp:
        (StringInstanceImp::StringInstanceImp): Construct a string with the right value
	instead of putting the string in later.
        (StringInstanceImp::get): Get the length from the string, not a separate property.
        (StringInstanceImp::put): Ignore attempts to set length, since we don't put it in
	the property map.
        (StringInstanceImp::hasProperty): Return true for length.
        (StringInstanceImp::deleteProperty): Return false for length.
        (StringObjectImp::construct): Call new StringInstanceImp constructor. Don't try
	to set a length property.

        * kjs/ustring.h: Make the rep deref know how to deallocate the rep.
        * kjs/ustring.cpp:
        (UString::release): Move the real work to the rep's deref, since the hash table
	now uses the rep directly.

        * kjs/object.h: Remove unused field.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@2749 268f45cc-cd09-0410-ab3c-d52691b4dbfc