[#32] BUGFIX: Unpublished mixtures not showing them category list. Closes #32.

* Change 'is_published' on mixture creation to False.
* Change test to validate unpublished mixtures not shown.
* Change local connection parameters to database.
* Disable long description autoescape.
* Change font family.
Merge branch 'bug-32-Categories_showing_unpublished_images' into develop