Reviewed by Anders.

    Reviewed by Anders.

        - changed deleteAllValues so it can work on "const" collections
          Deleting the values affects the values, not the pointers in the
          collection, so it's legitimate to do it to a const collection,
          and a case of that actually came up in the XPath code.

        * wtf/HashMap.h:
        (WTF::deleteAllPairSeconds): Use const iterators.
        (WTF::deleteAllValues): Take const HashMap reference as a parameter.
        * wtf/HashSet.h:
        (WTF::deleteAllValues): Take const HashSet reference as a parameter,
        and use const iterators.
        * wtf/Vector.h:
        (WTF::deleteAllValues): Take const Vector reference as a parameter.

        - added more functions that are present in <math.h> on some platforms,
          but not on others; moved here from various files in WebCore

        * wtf/MathExtras.h:
        (isinf): Added.
        (isnan): Added.
        (lround): Added.
        (lroundf): Tweaked.
        (round): Added.
        (roundf): Tweaked.
        (signbit): Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@14728 268f45cc-cd09-0410-ab3c-d52691b4dbfc