UI changes to make it more user friendly

This means Agents can no longer choose to add a BCC User while creating or responding to a Ticket.

This also means that if a User emails in a Ticket where someone is BCC'd, the Ticket will be created without the BCC'd User(s).

If an email is sent where the Department email is BCC'd, a Ticket is created for that Department and other Users in the email are added as Collaborators.

This also changes the response options for Agents. They now have the options to:
- Reply All (User + Collaborators)
- Reply to User (only the User)
- Do not Email Reply

(Previously the options were Reply All, Reply to User, Reply to CC + User, Reply to BCC, Do not Email Reply)

Unify ticket visibility as a routine to make sure it's applied uniformly.

This commit updates a bunch of files and changes a lot of phrases. Basically it extracts "Internal error occurred" from existing phrases.
I've re-ordered the phrases so "Internal error occurred" is always at the end after the actual informative error message.

Example comparison before and after this commit:
Before: 1 Phrase: "Internal error: Unable to print to PDF"
After: 2 Phrases: "Unable to print to PDF." + "Internal error occurred"

Fix a bug where it was impossible to disable ALL collaborators
Change recipients active/total count on update

* Log events for AJAX collaborator list edits
* Avoid extra selects for inline image handling
* Avoid using htmLawed to add target="_blank" and class="no-pjax" to links
  in the ticket thread
* Cache instances of IntlDateFormatter; seems expensive to set up
* Cache filetypes Yaml in APC if available
* Cache I18n::getDefaltLanguage() in the request
* Avoid extraneous usage of Model::_inspect and Model::$meta
* Add aggregated query support to the ORM
* Lazily compile SQL query for InstrumentedLists
* Apply `select_related` setting when setting up InstrumentedList instances
* Slight optimization in SqlCompiler::getField
* Avoid double compiling Sql annotations in the ORDER BY clause
* Cache Thread::getEntries
* Break out event types for ThreadEvent for more legible code
* Eliminate one query from Ticket::loadDynamicData
* Fix ticket number bolding if already answered
* Use dependent subqueries for ticket statistics in the queue page, which is
  significantly faster for large data sets (like hundreds of attachments or
  thread entries)
* Fixup sidebar layout on client knowledge base pages

Move collaboration implementation to thread level