AddrRange: Simplify Range by removing stream input/output

This patch simplifies the Range class in preparation for the
introduction of a more specific AddrRange class that allows
interleaving/striping.

The only place where the parsing was used was in the unit test.

src/base/SConscript

@@ -52,7 +52,6 @@ Source('output.cc')
 Source('pollevent.cc')
 Source('random.cc')
 Source('random_mt.cc')
-Source('range.cc')
 if env['TARGET_ISA'] != 'no':
     Source('remote_gdb.cc')
 Source('socket.cc')