Snakeoil

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- snakeoil.dist.distutils_extensions: Fix sdist builds for pkgcore.

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- snakeoil.demandimport: Add new module for lazy loading to replace
snakeoil.demandload.

- GPL2/BSD dual licensing was dropped to BSD as agreed by all contributors.

- snakeoil.klass: Add support for pull attribute list from __slots__ for
DirProxy.

- snakeoil.klass: Add SlotsPicklingMixin class to aid pickling class with
__slots__ defined.

- Minimum supported python version is now 3.6 (dropped python2 support).

- snakeoil.compression: Add generic archive/compressed file unpack support to
aid in pkgcore's unpack() move from bash to python.

- snakeoil.cli.arghparse: Add CopyableParser class that allows for shallow
copies of argparsers to be made that don't allow argument propagation to
their ancestors.

- snakeoil.iterables: Add partition() function that splits an iterable into two
iterables based on a given filter.

- snakeoil.log: Add suppress_logging context manager that allows suppressing
logging messages at a given level.

- snakeoil.cli.arghparse: Add custom help action to show man pages for --help
and still regular terminal output for -h.

- snakeoil.cli.arghparse: Add SubcmdAbbrevArgumentParser class that supports
abbreviating subcommands.

- Merge pkgdist back into snakeoil.dist.distutils_extensions as pip now
supports basic PEP 518 functionality so projects can depend on snakeoil to be
pulled in before running setup.py.

- snakeoil.cli.arghparse: Add append variants of csv arg parsing actions.

- snakeoil.decorators: Add new module for various decorator utilities currently
supporting splitexec, namespace, and coroutine decorators.

- snakeoil.contexts: Fix SplitExec when running under system tracers like coverage.

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- snakeoil.cli.tool: Tool: Force line buffering if redirecting or piping stdout.

- snakeoil.chksum: Add support for SHA3 and BLAKE2 hash functions -- BLAKE2 is
now required by pkgcore to generate new manifests in the gentoo repo.

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- snakeoil.cli.arghparse: ArgumentParser: Allow add_subparsers() to be called
multiple times, returning a cached action object for subsequent calls.

- snakeoil.cli.arghparse: ArgumentParser: Change subparsers property into an
immutable dictionary with keys and values as subparser names and objects,
respectively.

- snakeoil.contexts: SplitExec: Add support for passing back the exit status
of the child process as the 'exit_status' attribute on the context manager.

- snakeoil.process.spawn: Add bash_version method to get the system bash
shell version in the form of MAJOR.MINOR.PATCH.

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- snakeoil.contexts: SplitExec(): Run clean up method by default on SIGINT or
SIGTERM.

- snakeoil.contexts: Add syspath() context manager that mangles sys.path as
requested and reverts on exit.

- Fix documentation generation for modules with custom package dirs.

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- snakeoil.cli.arghparse: Add support to specify a default subparser for parser
instances. This allows for things such as adding conflicting options to both
the root command and subcommands without causing issues in addition to helping
support default subparsers.

- Add initial support to replace C extensions with cython modules.

- snakeoil.contexts: Add patch context manager for modifying module
attributes.

- snakeoil.cli.tool: New module for running scripts -- abstraction of pkgcore's
method for running its commandline tools.

- snakeoil.process.spawn: Imported from pkgcore.spawn.

- snakeoil.process: Add fallback parameter to find_binary().

- snakeoil.strings: New module for string-related methods.

- snakeoil.dist.generate_docs: Support custom doc generation by projects.

- snakeoil.osutils: Add force_symlink() method.