[Tachyon-14] TachyonURI (Client)

Internal methods that are deprecated should be removed as the refactor continues. Some questions left in the code as TODOs, will clean them up as they are addressed.
Since we use "TachyonURI("")" a lot, it may make sense to create a static final "EmptyTachyonURI" instance in TachyonURI class. Please note this and add it as a sub JIRA of this work.