Reviewed by Geoff.

    Reviewed by Geoff.

        - removed bool return value from JSObjectSetProperty, since it is inefficient and
        also doesn't work quite right
        - added JSObjectGetPropertyAtIndex and JSObjectSetPropertyAtIndex

        * API/JSObjectRef.cpp:
        (JSObjectSetProperty): Removed return value and canPut stuff.
        (JSObjectGetPropertyAtIndex): Added.
        (JSObjectSetPropertyAtIndex): Added.
        * API/JSObjectRef.h: Prototyped and documented new functions.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@15434 268f45cc-cd09-0410-ab3c-d52691b4dbfc