Includes changes by Stuart Morgan as well as my own.

        * Scripts/build-dumprendertree: Call the new setConfiguration function, and use XcodeOptions instead of
        symrootXcodeOptions to set the -buildstyle option.
        * Scripts/build-webkit: Ditto. Also remove the old way of supporting Xcode 2.1 and the old --debug option.
        The new --development option does the same thing.
        * Scripts/run-safari: Ditto.
        * Scripts/run-webkit-tests: Ditto.
        * Scripts/update-webkit: Ditto.
        * Scripts/set-webkit-configuration: Added. Sets the default configuration to Development or Deployment.

        * Scripts/webkitdirs.pm: use FindBin to find the WebKit directory; works no matter what the current
        directory is when invoking a script. Add code to determine the Xcode version so we can do the right
        thing for 2.0 and 2.1. Change the productDir function to return the appropriate per-configuration
        product directory. Read the default configuration from a file, overridable by a passed-in command-line
        option.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@9366 268f45cc-cd09-0410-ab3c-d52691b4dbfc