Update setuptools (#1024)

Upgrades setuptools from 39.0.1 to:
- 44.1.1 for Python 2.7 (since it's the last supported version)
- 43.0.0 for Python 3.4 (since it's the last supported version)
- 47.1.1 for Python 3.5+ (since we can't use 47.2.0+ until #1006 fixed)

https://setuptools.readthedocs.io/en/latest/history.html#v47-1-1

Fixes #949.
Closes #973.

test/run-features

@@ -44,7 +44,7 @@ testStandardRequirements() {
 
 testPipenv() {
   compile "pipenv"
-  assertCaptured "Installing pip 9.0.2, setuptools 39.0.1 and wheel 0.34.2"
+  assertCaptured "Installing pip 9.0.2, setuptools 47.1.1 and wheel 0.34.2"
   assertCapturedSuccess
 }