Add goog chrome postman API collection
API addition: files DELETE; Fix bug: only download a finalized file, Fix bug: download blocks of a file.
Fix bug: if the vault is not empty, return DELETE failure 412
Add more test cases
Merge remote-tracking branch 'repo/master' into random-bug-fix-2
update the postman scripts to reflect the right SHA1 blockid and fileid names in APIs
Merge pull request #37 from raxyu/random-bug-fix-2

multiple bug fix, and new apis.