Update README.md and HACKING.md and resulting yak shave.

sky/tools/shelldb

 #!/usr/bin/env python
 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from skypy.skyserver import SkyServer
 import argparse
 import hashlib
 import json
 import logging
@@ skipping 156 matching lines @@
         if os.path.commonprefix([path, SRC_ROOT]) == SRC_ROOT:
             server_root = SRC_ROOT
         else:
             server_root = os.path.dirname(path)
             logging.warn(
                 '%s is outside of mojo root, using %s as server root' %
                 (path, server_root))
         return server_root
 
     def _sky_server_for_args(self, args, packages_root):
-        # FIXME: This is a hack.  sky_server should just take a build_dir
-        # not a magical "configuration" name.
-        configuration = os.path.basename(os.path.normpath(args.build_dir))
         server_root = self._server_root_for_url(args.url_or_path)
-        sky_server = SkyServer(SKY_SERVER_PORT, configuration, server_root, packages_root)
+        sky_server = SkyServer(SKY_SERVER_PORT, server_root, packages_root)
         return sky_server
 
     def _find_remote_pid_for_package(self, package):
         ps_output = subprocess.check_output([ADB_PATH, 'shell', 'ps'])
         for line in ps_output.split('\n'):
             fields = line.split()
             if fields and fields[-1] == package:
                 return fields[1]
         return None
 
@@ skipping 324 matching lines @@
         args = parser.parse_args()
         pids = Pids.read_from(PID_FILE_PATH, PID_FILE_KEYS)
         exit_code = args.func(args, pids)
         # We could do this with an at-exit handler instead?
         pids.write_to(PID_FILE_PATH)
         sys.exit(exit_code)
 
 
 if __name__ == '__main__':
     SkyShellRunner().main()