encoding/tlv: Updating type assignment and fixing test cases

Type assignment now reflects the latest NDN-TLV spec.

Change-Id: Ibcd73a81ac72ebbd2897006f49518156aa9981a3
tools: Adding tlvdump app that visualizes TLV encoding stored in files

Change-Id: Iae29f56d5ab567653055dbbb8005f4bc10ae0dc0