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/key-locator.hpp b/src/key-locator.hpp
index 14a1b5e..f0700e2 100644
--- a/src/key-locator.hpp
+++ b/src/key-locator.hpp
@@ -13,7 +13,8 @@
 
 namespace ndn {
 
-class KeyLocator {
+class KeyLocator
+{
 public:
   class Error : public std::runtime_error
   {