Better handling of plural

[hugovk]

• "has" -> "have" for more than one
• add "and" to the package list, instead of "a, b, c" -> "a, b and c"

So instead of

"setuptools, distribute has been downloaded 16,668,162 times!"

print like

"setuptools and distribute have been downloaded 16,668,162 times!"

[aclark4life]

Thanks @hugovk !

[aclark4life]

https://pypi.python.org/pypi/vanity/2.0.5