tests: move update requiredest test to own test file More tests for this flag are coming in upcoming patches.

py3: add pycompat.unicode and add it to importer On python 3, builtins.unicode does not exist.

py3: add a bytes version of urllib.parse.urlencode() to pycompat.py urllib.parse.urlencode() returns unicodes on Python 3. This commit adds a method which will take its output and encode it to bytes so that we can use bytes consistently.

py3: replace str() with bytes()

metadataonlyctx: replace "changeset()[0]" to "manifestnode()" As Yuya pointed out [1], "changeset()[0]" could be simplified to "manifestnode()". I didn't notice that method earlier. It should definitely be used - it's easier to read, and faster. [1]: https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-March/095716.html

test-check-pylint: match its output "pylint --version" shows: pylint 2.0.0, astroid 1.5.0 Python 2.7.13 (default, Dec 21 2016, 07:16:46) [GCC 6.2.1 20160830] I got "Your code has been rated at 10.00/10" every time and didn't know how to turn it off. Therefore the fix.