Remove delivered-to addreses from list of recipients

This is necessary so we don't add delivered-to addresses to the list of
addressee/collaborators.
Ignore case for ticket variables on custom fields
Merge pull request #545 from greezybacon/issue/case-ticket-variable

Ignore case for ticket variables on custom fields

Reviewed-By: Peter Rotich <peter@osticket.com>
Allow searching for *any* priority
forms: Add placeholder and promts

Priority field and custom list fields have a prompt value (shows up only for
drop-down widget). And the short and long answer fields have a placeholder
configuration item.
Add placeholder for typeahead lists
staff ticket: Auto select 'Phone' source
staff ticket: Department is optional
staff ticket: Auto select singular help topic

If the system has only one help topic automatically select the help topic
and display any associated custom form.
Merge pull request #547 from greezybacon/issue/search-no-priority

forms: Allow searching any priority

Reviewed-By: Peter Rotich <peter@osticket.com>
Make sure Delivered-To addresses are NOT added as collaborators
Merge pull request #548 from greezybacon/issue/543

Simplify workflow for new ticket by staff

Reviewed-By: Peter Rotich <peter@osticket.com>
lint: Fix several E_NOTICE warnings from test script
lint: Add first of tests for mail parsing
Assume ISO-8859-1 when charset is unknown or bogus

Unfortunately, this is necessary because some mail clients send in content without defining
the charset or at worse using freaking wrong/invalid charsets like
'default'!
Add initial concept of a TNEF parser
Inspect file mime type if not provided
tnef: Detect corrupted TNEF streams
Merge pull request #551 from protich/issue/encoding

Assume ISO-8859-1 when charset is unknown or bogus

Reviewed-By: Jared Hancock <jared@osticket.com>
Merge pull request #544 from protich/feature/delivered-to+collaborators

Remove delivered-to addresses from list of recipients

Reviewed-By: Jared Hancock <jared@osticket.com>