Stop comparing repr()'s in TestEntryPoint

Adjust expectation that 'extra' is not in the marker evaluation if no extras demanded the requirement.

Reinstate the or guard in WorkingSet._markers_pass

In Python 3, the default order of iterables can not determined,
so comparing the repr of objects that include tuples is not static
like it is under Python 2. Compare the attributes of EntryPoint
instead, making sure to sort .attrs and .extras.

Closes: #526

Restore evaluating environment markers in WorkingSet

Correctly deal with parsed requirements that include extras as a
marker inside WorkingSet that are populated from METADATA inside
wheels, like we get from pip>=7.

This partially reverts commit 04d10ff0.

Closes: #523

Drop unused safe_repr function

When _assertIn was removed from test_resources, the safe_repr
function was not dropped, leaving it with no callers, so drop it.

--HG--
branch : distribute

Update vendored packaging to 16.6

Don't test the bootstrap script. It fails when deploys are happening, which is common when releases are being made.

Logic in upload_docs will only trigger docs build if no docs dir was specified, so explicitly build during release. Fixes #524.