puppetlabs_spec_helper doesn't allow pinning to a branch instead of a
tag/ref, and the requires are in the apt_conf not on the files.

Test fixes

Testing unattended upgrades

Test updates

Since this module contains no Ruby code there's really no point in
running a matrix for all Ruby versions. We trust Puppet to work on the
different Ruby versions so all we need is to run the different versions
of Puppet.

We use Ruby 2.1.6 since 2.2.x causes Puppet 3 and 4 to crash.

We need to allow Puppet 4 builds to break right now because rspec-puppet
doesn't work with it.

travis: Test only latest Ruby and Puppet.

This will stop us from building branches that people with push access push to instead of fork+PR.

Add metadata.json

Apt class takes care of this well enough for us.

First take the defaults and the merge the user passed in options into
them, not the other way around as then our defaults end up overriding
some of the keys users pass in.

When MailOnError is not set it will mail for everything by default so it
only makes sense to have that key if we want it set to true.

Setting it to 'undef' makes it the string undef, not having it set makes
it undef/nil for Puppet.

We now test:
* Default behaviour on Debian
* Default behaviour on Ubuntu
* Setting all the possible settings

The `size` hash could only ever have the `max` key so it makes more
sense to have this as a plain value.

This also upgrades the dependency on stdlib to 4.6.0 since we're using
the new `validate_integer` function.

Closes: #6

* Remove acceptance test runner
* Remove blacksmith

* development group is not needed (don't use blacksmith)
* systems_tests is not needed (no Beaker tests)

Rake travis changelog

When specifying `rvm: 2.1` it'll automatically pick the latest Ruby 2.1
available.

Setup deploy

* Update CHANGELOG

Prepare 1.0.1 release: