Switch from `.dev` to `.test`

In light of Google enabling HSTS on the .dev TLD. Maintains support for .dev for backward compatibility.

The .test TLD is reserved (along with .example, .invalid, and .localhost) per RFC 2606 and RFC 6761: https://tools.ietf.org/html/rfc6761#section-6.2

    6.2.  Domain Name Reservation Considerations for "test."

    The domain "test.", and any names falling within ".test.", are
    special in the following ways:

    1.  Users are free to use these test names as they would any other
    domain names.  However, since there is no central authority
    responsible for use of test names, users SHOULD be aware that
    these names are likely to yield different results on different
    networks.

    2.  Application software SHOULD NOT recognize test names as special,
    and SHOULD use test names as they would other domain names.

    3.  Name resolution APIs and libraries SHOULD NOT recognize test
    names as special and SHOULD NOT treat them differently.  Name
    resolution APIs SHOULD send queries for test names to their
    configured caching DNS server(s).

basecamp / pow

Switch from `.dev` to `.test` #547