Add callback manager

Callback manager sets up matches and sets properties on
dbus.

Tested: used sensor override to make sensors assert
critical and warning interfaces and saw led change. also
caught a few buggy threshold settings using led.

Change-Id: I06c164b749febbc3e81cb3db5f7a0a2b72b3678f
Signed-off-by: James Feist <james.feist@linux.intel.com>
diff --git a/callback-manager/LICENCE b/callback-manager/LICENCE
new file mode 100644
index 0000000..729f4d4
--- /dev/null
+++ b/callback-manager/LICENCE
@@ -0,0 +1,13 @@
+Copyright 2019 Intel Corporation
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.