DB update script for 1.0.2

This adds field settings for 'allow-new', 'allow-edit', 'allow-link'
features.

Re: #2
UI and logic for saving permissions settings

This change adds 3 checkboxes, one for each permission setting.

The name of the field's settings also changed to use underscores (_) instead
of dashes (-) since other settings also use underscores.

Re: #2