tests: demonstrate too many spaces in olog -p output with word-diff

rewind: add --keep flag that "doesn't modify working directory" The actual logic is more complicated than the flag description, but it's sufficiently similar to other --keep flags in action. Unlike strip (or prune), rewind always needs to modify the working directory to commit new revisions that "revive" old ones [1], see _revive_revision() (and rewriteutil.rewrite()). Because of that we don't prevent rewind from modifying wdir, but instead use hg.updaterepo() to update to the old changeset after the "revival" process is complete. Then we rebuild the dirstate based on the commit that rewind would update to without --keep. Since dirstate.rebuild() doesn't restore status of some files (added, removed, also copies and renames), we rely on cmdutil.revert(). It's a fairly crude solution and needs to be removed when implementing the missing copy tracing between oldctx and newctx (which are related only by obsolescence). [1] IOW this means that --keep doesn't allow rewinding if wdir is dirty (unlike e.g. strip).

tests: separate rewinding of merge commits, temporarily drop an error case The error case will come back in the following commit, because it organically fits there without the need of a separate working clone.

python3: add python3 beta support to the CHANGELOG

python3: mention beta Python 3 support in README

python3: add supported python versions to setup.py Mercurial technically can support Python 3.5 (although no lower, see its setup.py), but `evolve` probably won't because it represents more work for an underrepresented Python version. If you happen to *really* need evolve to work on Python 3 and you're reading this message, send an email to the mailing list, or contribute patches.

test: update output for wider cache warming CORE-TEST-OUTPUT-UPDATE: cdf0e9523de1

branching: merge with stable format source worked smoothly :-)

python3: use format-source to run byteify-strings in .py files Using the format-source extension smooth out the pain of merging after auto-formatting. This change makes all of the Evolve test suite pass under python3 and has added benefit of being 100% automated using mercurial's `byteify-strings` script version 1.0 (revision 11498aa91c036c6d70f7ac5ee5af2664a84a1130). How to benefit from the help of format-source is explained in the README.

topic: add a new random attribute (This is mostly an excuse to test the format-source setup)

python3: enforce byte prefix for vfs.open() Changeset ea8da5aa23c6e723d7f0006387a1a20eef58fc9a added raw prefix to open(), but also to vfs.open(). The latter only handles bytestring arguments.

python3: add raw prefix to sqlite isolation level

python3: add ignore block around python 2 compatibility if branch

flake8: silence F633 error