MANIFEST.in: include header files in sdist
Adds 'reprounzip info' command
Makes entry points return some information

The setup function defined by the entry_point mechanism now returns a
list of dicts, which each contain information about a specific unpacker.
The "official" entry_point have been updated to return that information,
which currently includes:
  - 'name', the readable name of the unpacker (that is the argparse
    command group)
  - 'test_compatibility', which indicates if the unpacker will work on
    the current machine with the given pack file

This will be useful to list and test the available unpackers.
Merge branch 'unpacker-info' into 'info-command'

Conflicts:
	reprounzip/reprounzip/reprounzip.py
Makes 'reprounzip info' print compatible unpackers
Simplifies test_compatibility
Simplify test_compatibility protocol
Merge branch 'unpacker-info' into 'info-command'
Renames reprounzip/reprounzip to reprounzip/main

I don't think these conflicts should happen, so long as absolute_import
is used in the right place. But they do... (pkg_resources' fault?)
Merge branch 'master' into 'info-command'
Makes tests/run.py run 'reprounzip info'
Checks for Linux before comparing distrib/arch
Adds a readable "not POSIX" error message

Previously, unpacking with 'directory' or 'chroot' would fail when
constructing a Path from a PosixPath was wrong (like on Windows).
Adds vagrant --no-use-chroot, defaults to chroot
Adds installpkgs --missing

Only installs packages whose files were not packed.
Adds installpkgs --summary

The package installer now returns a dictionary giving the current status
(installed version or not installed) of requested packages. This is used
by the installpkgs command to print out information, and to implement
installpkgs --summary.
Makes sure pip calls setup.py scripts correctly
Removes PKG_DOESNT_EXIST status

It seems that dpkg-query might either return a line without a version
number or print an error and return 1, if a package that is not
installed is queried. With this commit, we handle both cases as "package
is not installed" (PKG_NOT_INSTALLED).
Fixes host file copy logic in chroot
Fixes host file copy logic in vagrant

Note: here the host is the virtual machine (but outside the chroot).