parity file computation and storage
fixed test mock and include .par2 index file
travis req
try root
Merge branch 'feature/parity_files' of https://github.com/icereval/osf-upload-service into backups

Conflicts:
	cloudstorm/queue/tasks.py
	cloudstorm/storage.py
	tests/test_queue.py

Changes:
Retry each parity file push separately.
Skip parity files for primary files that already exist.
Add tests for hash mismatch.