Update Readme-osx-10.9.md
Hardcode python2.7 in the packaging script

This is necessary when packaging the SDK for CentOS 5 and 6 (in which
the default python is 2.6).

Also parameterize the target interpreter #! line in the packaging
script.

This reverts a portion of 5630a72 that incorporates #! line rewriting
into the python build target. It's generally inappropriate to do that
rewrite except when packaging for a specific target in a controlled
build environment, since we don't have enough information about which
interpreter installation is being used for the build, or which one
will be used in the target system, or the relationship between the
two.
PTFM-7006 Adding bash helpers for upload/download of multiple files.

Summary:
These are implemented as python scripts, called dx-upload-all-outputs, dx-download-all-inputs,
dx-download-input.

Test Plan: Added unit tests that work locally, written in python.

Reviewers: klai, psung

Reviewed By: klai, psung

Subscribers: akislyuk

Differential Revision: https://phabricator.dnanexus.com/D19
dxpy: 503/Retry-After responses do not count against max_retries

Add some assertions to clarify the control flow.
Skip test that would run jobs
PTFM-12403: Add a regression test for tab-completing dx upload dir/
PTFM-12403: Amend test to also test dx build tab completion
Add -h for dx-upload-all-outputs

Also unify the style with the dx-download-all-inputs tool
Changelog and version updates for v0.107.0