Refactor packages filtering

Do it so we avoid repeating code.

Signed-off-by: Martin Abente Lahaye <tch@sugarlabs.org>
Massive re-refactoring

Basically, moved libraries inside helpers directory so helpers
could use it directtly without dirty tricks.

Also, separated class-like and script-like sources between helpers
and libs.

Lastly, re-factored repositories and packages logic so it could be
used by different helpers.

Ah! and allowed to specify repos for updates.
Add README

Signed-off-by: Martin Abente Lahaye <tch@sugarlabs.org>
Support for multiple keywords

Add support for multiple keywords in OR logic, also,
use this new feature for updates repositories updates.
Update README

Signed-off-by: Martin Abente Lahaye <tch@sugarlabs.org>
Release 0.0.1

Signed-off-by: Martin Abente Lahaye <tch@sugarlabs.org>