Attachment settings are now exclusively handled by the settings on the
ThreadEntry field on the ticket details form. Enabling attachments as well
as tuning attachment validation settings are all handled from the one place
now.

Only one file is supported at a time now; but at least the files are saved
and displayed in the event of validation errors.

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.

Add context to ticket state name (noun) and action (verbs)

Conflicts:

	include/class.forms.php

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 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 allows for subclasses to define how the choice is formatted.
Split ticket status states into public and private

Previously, the characters would be removed and the data would be considered
empty which would bypass validation and clear the phone number on save
rather than triggering a validation error.

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

Add multiselect  option to selection and choices fields.