PTFM-12654 Fix dx download -r proj:/folder
Prevent filesystem collisions in dx download

This prevents unhandled errors when running commands of the form "dx
download x*" where x is both a file and a folder name.
Simplify checks in 3e63057
Interpret _DX_DEBUG only if it's an integer

Summary:
_DX_DEBUG is now interpreted as an integer. Updated uses of _DEBUG
accordingly.

Test Plan: tested by hand

Reviewers: akislyuk

Reviewed By: akislyuk

Differential Revision: https://phabricator.dnanexus.com/D95
Fix NameError introduced in 535b041
dx download -r: only reconstruct the last path element
Bump psutil dependency from 1.2.1 to 2.1.1
Revert "dx download -r: only reconstruct the last path element"

This reverts commit 70ad4d27d9e75a9f33e3df5530ed1649b0bed0b9.
Revert "Revert "dx download -r: only reconstruct the last path element""

This reverts commit 031efe2b1a36f20431a4b693e04533773c111859.

Erroneously reverted commit
PTFM-13212 Treat all greet route errors in dx login as non-fatal
Bugfix for dx download -r when given a relative path
Further bugfix for dx download -r for relative paths with trailing slash
Support building with openjdk 7 (in particular for Ubuntu 14.04)
Changelog and version updates for v0.117.0