Fix improper binary filename normalization for packages with hyphens in the names

[dan-blanchard]

As you can see at https://pypi.python.org/simple/msgpack-python/, if a package name has hyphens in it, the binary filenames should have them replaced with underscores.

For msgpack-python that would be:

• msgpack_python-0.2.0-py2.7-win-amd64.egg
• msgpack_python-0.4.7-cp27-none-win32.whl
• msgpack-python-0.4.7.tar.gz

Note that the tarball still is expected to have hyphens that match the package name.

Without this fix, wheel cannot properly interpret the filenames of packages downloaded from pip2pi servers, because it uses the following regex to parse it:

WHEEL_INFO_RE = re.compile(
    r"""^(?P<namever>(?P<name>.+?)(-(?P<ver>\d.+?))?)
    ((-(?P<build>\d.*?))?-(?P<pyver>.+?)-(?P<abi>.+?)-(?P<plat>.+?)
    \.whl|\.dist-info)$""",
    re.VERBOSE).match

[dan-blanchard]

The test failures appear to be Travis issues and not at all related to my change.

[yjjnls]

#85 has fixed this problem, but the PR hasn't been merged.

[safiyat]

Closed in #85.