This will be useful for maintaining arbitrary list of items. ListObject
should be used in the place of ArrayObject

Furthermore, revamp the __cdata system to better support multiple selection
fields. Drop the `.._id` fields and use a coalesce of the ID value of the
entry value or the entry value itself. For JSON backed fields, strip some
JSON characters to result in a comma-separated list.

The search engine now uses MySQL FIND_IN_SET to analyze a search selection
in advanced searches. Also, interaction with the MySQL full text search
backend is fully supported.

Not just the SelectionField. This will make room for the InlineFormField

This will allow for more complex widgets to be added as plugins which
include css and javascript media files without manually adding header or
footer lines.

And allow for @context to add context to the bare string literal. For
instance,

    /* @trans, @context "noun" */ 'Open'

Would mark the string 'Open' translatable with context "noun".

Always support and consider multiple values — even using the typeahead
widget.

Always save a key/value hash of the selected value(s). However, if the field
does not have the multivalue configuration setting, then retrieve just the
key with the to_php() function. to_database(), however, will always return a
JSON string with the value(s) formatted as a hash array.

This patch fixes an issue where a fatal error would be triggered if the
current value of a selection field on a custom form was a custom list item
that has since been deleted.

Also add some logic to the POT builder to warn about incorrect arguments to
the __() function and friends as well as warn about _() usage.

When managing properties of list items

  * Paper sizes
  * More prompts on ticket filters

This patch fixes a glitch in the dynamic forms processing system preventing
the validation and capture of data for help topic custom fields. Now the
`$vars` managed inside of `Ticket::create` is connected directly to the
`DynamicFormEntry` created for the data rather than using the magical
connection to `$_POST`.

Add multiselect  option to selection and choices fields.

Add an interface for custom list items.
Implement CustomListItem for built-in and custom lists.

Generalize custom list interface in order to provide for facility to manage
system's built-in list like ticket statuses, priorities ...etc.

Several places in the code initialize a list of objects from the database
and only fetch one item. In certain instances (which seem almost like a race
condition), MySQL will feel like there are more records available in the
database and will complain with "Commands out of sync, you can't run the
command now".

This patch addresses the issue by utilizing the ::one() method of the
QuerySet where only one record is expected. The ::one() method is further
designed to fetch all one results (which satisfies the MySQL client library)
and return the first item.