Test the last remaining untested code.

Without the ALPM_DB_VERSION version the alpm.Handle cannot be
initialized.

This fixture fakes a pacman package for example required for pyalpm to
test Handle.load_pkg.

This fixture can generate a pacman syncdb from a dictionary.

The _generate_localdb fixture only created the required entries for one
package not all provided packages.

Use a Makefile for linting and test target to make it easier to develop.

The shared fixtures should be scoped session so consumers can define
their own desired scope.

This plugin aims to provide an easy way to create and use a pacman
localdb. For projects depending on pacman local db such as pyalpm or
syncdb's such as archweb.