Handle release parameter more sensibly in force manifest.

Use release parameter to construct $release_string.

The release parameter may also be set to false to use the system's
default release (so just force a specific version). Use false as the
default setting instead of 'testing'.

Change $install_check to also check if package is installed from the
right release, instead of just checking the version.
Don't use hardcoded provider in force manifest.

Use $apt::params::provider instead.
Update specs to test all parameter cases
Update example apt::force tests
Added class for managing unattended-upgrades
Added spec test for unattended-upgrades class
[#153] Rename unattended_upgrades s/-/_/

It's preferable to use underscores rather than hyphens in class names. Refs:

- http://projects.puppetlabs.com/issues/5268
- http://docs.puppetlabs.com/puppet/3/reference/lang_reserved.html#classes-and-types
[#153] Convert t/f params to bools and validate

Per lint check: http://puppet-lint.com/checks/quoted_booleans/
[#153] Variablise file paths in unattended spec

Reduce some duplication of long file paths.
[#153] Test defaults for some unattended params

For params which have any logic embedded in the template:

- origins
- blacklist
- mail_to
- dl_limit
[#153] Install unattended configs after package

To ensure that the default configs from the package are always overwritten
within a single Puppet run.
[#153] Remove trailing whitespace from spec.
Merge pull request #153 from drbop/drbop_unattended_upgrades

Class for managing unattended-upgrades
Prepare 1.3.0 release.
Merge pull request #162 from apenney/130-release

Prepare 1.3.0 release.
add an updates_timeout option to apt::params (PR fix)
Merge pull request #167 from madeddie/master

add an updates_timeout option to apt::params (PR fix)
Add initial rspec-system tests.

This covers:

apt::builddep
apt::key
apt::ppa
apt::source
apt
Merge pull request #168 from apenney/rspec-system

Add initial rspec-system tests.
This switches us to doing a `test -s` instead of checking for the
files existence as add-apt-repository --remove leaves a 0 byte file
behind instead of deleting everything properly.