This connects us via a domain hosted on AWS which should provide
performance benefits for users running Clair on AWS and alleviate load
from the NIST campus network.
Fixes#575.
This removes the `types` package instead moving the contents to the
top-level clair package.
This change also renames the `Priority` type to `Severity` in order to
reduce confusion.
This change also removes the IsValid method and replaces it with a safe
constructor to avoid the creation of invalid values.
Many docstrings were tweaked in the making of this commit.
