Modify parser and add mako scripts for watch on object path

Added support for watch and callback on 'interface added'
signal for the specified object paths.

Added mako scripts for events to auto create callback
and watch objects for the specified object path groups.

Clients specify object paths to watch and callbacks to
invoke in the config.yaml file

Change-Id: I3fa2ea1520649120b927c0cb83a16e5cace2f24e
Signed-off-by: Marri Devender Rao <devenrao@in.ibm.com>
diff --git a/src/templates/eventpath.mako.cpp b/src/templates/eventpath.mako.cpp
new file mode 100644
index 0000000..3fa9fb9
--- /dev/null
+++ b/src/templates/eventpath.mako.cpp
@@ -0,0 +1 @@
+std::make_unique<SNMPTrap<${c.eventType}>>()