Do some retries if get_or_connect fail

A better implementation, with a new flag on the job, will be added later
Add missing scripts module in package
Bump to version 0.0.10
Add a `queued` field to the `Job` model

The goal is to be able to know if a job is currently managed by a queue,
regardless its real status: waiting, delayed or running.

With this we can call `add_job` and not creating a new job even if the
current existing one is in the `running` or `delayed` status, which
wasn't the case before this because with used to check the `status`
field.

Closes #8
Bump to version 0.0.11