Merge pull request #1367 from jeffmccune/fix/master/ipaddress_specs

(maint) Skip IPv6 examples that cannot pass on MRI 1.9.3-p327
Fixup use of conditional pending

Without this patch the tests aren't actually getting marked as pending
because exceptions are being raised in the before blocks.  This patch
addresses the problem by switching the declaration references to a lazy
evaluated let method rather than a preemptive before block.  This
prevents the exception and allows the pending methods to execute.
(maint) Add Travis CI Support

This patch adds Travis support.  It also makes sure that `bundle install
--path vendor` works with `bundle exec rake spec`.

This patch should coincide with enabling Travis CI support for pull requests.
A build status image is also included in the project README.