py3: use print_function in hypothesishelpers.py

tests: use absolute_import in hypothesishelpers.py

py3: use print_function in get-with-headers.py

py3: use print_function in generate-working-copy-states.py

py3: use print_function in filterpyflakes.py

py3: use print_function in test-ancestor.py

py3: use print_function in seq.py

py3: use absolute_import in seq.py

parser: move parsererrordetail() function from revset module This will be used by common alias functions introduced by future patches.

hgweb: fix links in atom-branches

revset: prevent infinite recursion on pypy as explained in the commit, __len__ cannot do [x for x in self] because that can potentially call __len__ again, causing infinite recursion

pypy: fix doctests for pypy optimizations PyPy would sometime call __len__ at points where it things preallocating the container makes sense. Change the doctests so they're using generator expressions and not list comprehensions

largefiles: replace invocation of os.path module by vfs in reposetup.py This commit is part of bigger effort described in 'Windows UTF-8' plan.

largefiles: replace invocation of os.path module by vfs in overrides.py This commit is part of bigger effort described in 'Windows UTF-8' plan. It is not changing all invocations but the ones where change is obviously correct and doesn't require complicated changes.

bundle: warn when update to revision existing only in a bundle (issue5004) Now its done silently, so unless user really knows what he is doing will be suprised to find that after update 'hg status' doesn't work. This commit makes also merge operation warns about missing parent when revision to merge exists only in the bundle.

tests: fix builtin module test on pypy On pypy datetime and cProfile are modules written in Python, not in C. For the purpose of this test, just list them explicitely as builtins, which silences warnings about them being imported before stdlib modules.