Convert old-style classes in Builder.py to new-style classes.
Convert old-style classes in Builder.py to new-style classes.

timj/scons,timj/scons,andrewyoung1991/scons,timj/scons,timj/scons,timj/scons,timj/scons,andrewyoung1991/scons,andrewyoung1991/scons,andrewyoung1991/scons,andrewyoung1991/scons,andrewyoung1991/scons,timj/scons,timj/scons,andrewyoung1991/scons,andrewyoung1991/scons,timj/scons,andrewyoung1991/scons