Built-in columns

For common use-cases the following columns are included:

• BooleanColumn -- renders boolean values
• Column -- generic column
• CheckBoxColumn -- renders checkbox form inputs
• DateColumn -- date formatting
• DateTimeColumn -- datetime formatting in the local timezone
• EmailColumn -- renders <a href="mailto:..."> tags
• FileColumn -- renders files as links
• JSONColumn -- renders JSON as an indented string in <pre></pre>
• LinkColumn -- renders <a href="..."> tags (compose a Django URL)
• ManyToManyColumn -- renders a list objects from a ManyToManyField
• RelatedLinkColumn -- renders <a href="..."> tags linking related objects
• TemplateColumn -- renders template code
• URLColumn -- renders <a href="..."> tags (absolute URL)