Add note for some functions and fix document error

Change-Id: Ide2500c393d2a135f343263dd8c3e3f0e644efe0
diff --git a/specification.rst b/specification.rst
index f221380..1548d9c 100644
--- a/specification.rst
+++ b/specification.rst
@@ -10,7 +10,7 @@
   - Centralized configuration – all configuration is done on controller instead of each individual switch
   - Centralized role-based access control (RBAC)
   - Automatic host (end-point) discovery – attached hosts, access-devices, appliances (PNFs), routers, etc.
-  - based on ARP, DHCP, NDP, etc.
+    based on ARP, DHCP, NDP, etc.
   - Automatic switch, link and topology discovery and maintenance (keepalive, failure recovery)
 
 L2 Features
@@ -152,4 +152,4 @@
   - (in labs/trials) OF-DPA software community version available from ONF (for
     switch models based on Trident and Tomahawk, not Qumran)
 
-  - (in labs/trails) Stratum available from ONF
+  - (in labs/trials) Stratum available from ONF