The hash passing to the with method is cleaner and closer to puppet code, so
all of the with_$param have been replaced with with($hash). This also
includes two minor whitspace changes to unstable.pp and source.pp.
This also replaces the ternary switch on param_set with a hash merge,
which is cleaner and will support more use cases.
This commit adds full coverage for the apt module as it currently exists. It
adds rspec-puppet tests for the defines (apt::builddep, apt::force, apt::pin,
apt::ppa, apt::source) and classes (apt, debian::testing, debian::unstable,
apt::params, apt::release).
