exceptions: Make Tlv::Error a base class for all packet-processing exceptions

This commit also includes a number of code style fixes.

Change-Id: I44f83915e733b43d5f43b4266902c8262e928d91
Refs: #1528
diff --git a/src/security/encryption-manager.hpp b/src/security/encryption-manager.hpp
index a6f319b..f4f43b5 100644
--- a/src/security/encryption-manager.hpp
+++ b/src/security/encryption-manager.hpp
@@ -13,7 +13,8 @@
 
 namespace ndn {
 
-class EncryptionManager {
+class EncryptionManager
+{
 public:
   virtual ~EncryptionManager()
   {