Use 'with' statements.
Bug #418475: Handle PermissionError caused by unreadable /etc/portage/modules.
chpathtool: standardize quote style
chpathtool: use built in %(prog)s for usage
chpathtool: clean up arg parsing to use proper argparse module

Also throw in some documentation for good measure since not everyone knows
what this thing does.
xattr-helper: use upper caps for module constants
xattr-helper: add docstrings to more places
xattr-helper: use ValueError when the input is wrong

This is the standard exception for when the input is incorrect.
xattr-helper: standardize quoting style a bit
xattr-helper: refactor dump_xattrs to make it a bit more readable

Pull the common qoute chars out into a var and use % with format
strings rather than mixing + in between.
xattr-helper: clean up command line interface

This uses the standard argparse fields rather than open coding things
ourselves.  It also makes it a bit easier to test as you can now pass
paths on the command line in addition to stdin.
pym/util: clean up style a bit

Shouldn't be any functional changes here.
helper-functions.sh: sync with multiprocessing.eclass

This pulls in (among other thing) portability fixes.

URL: https://bugs.gentoo.org/487056
movefile: simplify xattr fallback logic

The "with open()" construct handles exceptions just fine.
tests: add assertExists/assertNotExists helpers

This makes it easy to assert the state of paths and when things fail,
get a good error message in the process (without having to dig into
temp dirs by hand).

This has largely been cribbed from ChromiumOS's chromite module.
fix typo causing a "os" is not defined test error.
tests: support standard unittest.SkipTest exceptions
tests: support assertIn/assertNotIn in python-2.6
Fix a typo.
Show packages forcing rebuilds (bug 472104)