add missing header end comments

- ensures a consistent usage in header files
- also add a blank line after the copyright header where missing
- also remove orphan new-lines at the end of some files

src/crypter.h

@@ -192,4 +192,4 @@ public:
     boost::signals2::signal<void (CCryptoKeyStore* wallet)> NotifyStatusChanged;
 };
 
-#endif
+#endif // __CRYPTER_H__