shill: Implement service sorting

Sort the list of Services for presentation to
RPC callers, essentially copying the current flimflam
sorting criteria.  Introduce the TechnologyOrder to
the Manager.

BUG=chromium-os:20114
TEST=New unit tests

Change-Id: I766b2297ba3170a7a6ab5adfe68425a8011be4fb
Reviewed-on: http://gerrit.chromium.org/gerrit/8205
Tested-by: Paul Stewart <pstew@chromium.org>
Reviewed-by: mukesh agrawal <quiche@chromium.org>
diff --git a/cellular_service.cc b/cellular_service.cc
index f2c2b10..be5af33 100644
--- a/cellular_service.cc
+++ b/cellular_service.cc
@@ -55,6 +55,10 @@
   cellular_->Activate(carrier, error);
 }
 
+bool CellularService::TechnologyIs(const Technology::Identifier type) const {
+  return cellular_->TechnologyIs(type);
+}
+
 string CellularService::GetStorageIdentifier() {
   string id = base::StringPrintf("%s_%s_%s",
                                  kServiceType,