Soft merge of uri branch
separate tachyonfs and tachyonfile phase 2
tweak tachyonfile
Clean up TachyonURI code
Address TODOs in TachyonURI
Merge pull request #384 from calvinjia/tachyon-14

[Tachyon-14] TachyonURI
tweak tachyonuri
Merge branch 'master' of https://github.com/amplab/tachyon into fqdn