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/.gitignore b/callback-manager/.gitignore
new file mode 100644
index 0000000..0cb1d79
--- /dev/null
+++ b/callback-manager/.gitignore
@@ -0,0 +1,3 @@
+build/*
+oe-logs
+oe-workdir