Bug 1259551 - Upgrade vendored virtualenv to 15.0.1; r=ted

While we're addressing virtualenv foo, let's ensure we are running
the latest version. This also pulls in newer versions of pip (8.1.1),
setuptools (20.3), and wheel (0.29.0).

MozReview-Commit-ID: G5uSy66Kd6u

python/virtualenv/tests/test_cmdline.py

@@ -0,0 +1,44 @@
+import sys
+import subprocess
+import virtualenv
+import pytest
+
+VIRTUALENV_SCRIPT = virtualenv.__file__
+
+def test_commandline_basic(tmpdir):
+    """Simple command line usage should work"""
+    subprocess.check_call([
+        sys.executable,
+        VIRTUALENV_SCRIPT,
+        str(tmpdir.join('venv'))
+    ])
+
+def test_commandline_explicit_interp(tmpdir):
+    """Specifying the Python interpreter should work"""
+    subprocess.check_call([
+        sys.executable,
+        VIRTUALENV_SCRIPT,
+        '-p', sys.executable,
+        str(tmpdir.join('venv'))
+    ])
+
+# The registry lookups to support the abbreviated "-p 3.5" form of specifying
+# a Python interpreter on Windows don't seem to work with Python 3.5. The
+# registry layout is not well documented, and it's not clear that the feature
+# is sufficiently widely used to be worth fixing.
+# See https://github.com/pypa/virtualenv/issues/864
+@pytest.mark.skipif("sys.platform == 'win32' and sys.version_info[:2] >= (3,5)")
+def test_commandline_abbrev_interp(tmpdir):
+    """Specifying abbreviated forms of the Python interpreter should work"""
+    if sys.platform == 'win32':
+        fmt = '%s.%s'
+    else:
+        fmt = 'python%s.%s'
+    abbrev = fmt % (sys.version_info[0], sys.version_info[1])
+    subprocess.check_call([
+        sys.executable,
+        VIRTUALENV_SCRIPT,
+        '-p', abbrev,
+        str(tmpdir.join('venv'))
+    ])
+