Multilanguage Support via gettext

- added gettext encapsulations to all texts i thought necessary
- added fallback function for the case that the gettext extension isn't loaded
- added browser language detection
- added gettext to the list of optional extensions in setup
- rewritten some of the texts to use sprintf instead of appending strings
- added german translation file
- removed mark_overdue-confirm from cannedresponses.inc.php

extend multi language support and a fex fixes

- Better detection of translation files
- Added functionality to redirect language codes (see redirecting
language codes)
- Ticket Status can be translated
- The Datepicker can be translated
- Extended functionality of 'testlang.php' to show what language code is
used to translate

Forgotten to apply a patch from RC5 to RC6

- Forgotten to change $var to $vars in line 380 of class.mailfetch.php
- Removed unneeded comment

Added php_gettext as primary translation engine

- Added php_gettext support (thanks to Danilo Segan and Steven
Armstrong)
- php_gettext is now the primary translation engine
- Extended language detection functionality

Add error/misconfiguration checks and fix undefined variables

Make the organization page happy!

Departments without email will use the system default email as the default
outgoing email.

Previously we required an account to associate a user to an organization.

This patch partially reverts the previous database migration patch which
added a primary key to the table on the `thread_id` column. This column
cannot be used, because there may be multiple entries for thread_id = 0.

This also allows ticket_collaborator.isactive to be negative, as well as
adds the database portion of regex support for ticket filters.

Add `attrs` field for backend state information (multi-part migration,
multi-part upload, etc). Change `size` to be an integer rather than text
field. (Storage space will be about the same, but int makes more sense).
Size the `key` and `signature` for ~512 bits. The base64 encoding allows
6-bits per char. At 86 chars, we have 516 bits maximum space.

Fixes the rewriting of the `key` field in the ticket thread body. The
storage de-duplication system may replace the `key` value with an existing
one. The ticket thread system will use the `key` value assigned when the
file is committed to the database or the existing key of the duplicate file.

Also fixup installation issues with the attachment storage plugin
architecture

  * Include a `bk` column to store the storage backend
  * Include a `signature` column which represents a repeatable hash of the
    file contents
  * Rename `hash` to `key` since it isn't a real hash

Conflicts:

	include/upgrader/streams/core.sig

And install initial data in target language. Also configure help tip
popovers to be in the configured, default system language.

This patch allows for the specification of a socket in the database hostname
field, such as localhost:/path/to/mysql.sock

This includes the initial concept of pluggable authentication along with the
initial concept for a plugin management system.

line 199: in case of custom upgrade streams, variable $signature contains the last value from the foreach cycle at line 130, not the core schema signature!

line 209: if we do not insert schema signatures for each custom stream, after install osTicket thinks it needs an upgrade and gets stuck (see function isUpgradePending() in class.ticket)

Overhaul the popup tips from the installer to make them translatable and
work toward popovers for all the admin and staff panel settings.

Validate port during installation

Add help information about the non-standard port number to the popup tips in
the install screen.

Support MySQL 'localhost' connections using a non-standard port number.
Ordinarily, MySQL will ignore the port setting on *nix systems if the host
is specified as 'localhost'

Implements/Fixes #769

    * Ticket created after installation
    * Ticket created after upgrades

Add help information about the non-standard port number to the popup tips in
the install screen.

Support MySQL 'localhost' connections using a non-standard port number.
Ordinarily, MySQL will ignore the port setting on *nix systems if the host
is specified as 'localhost'

Fixup several minor bugs concerning initial experience

Moved to an initial form which specifies the ticket's priority and issue and
changed the rendering to render things properly. Now the user can decide
where priority shows on the client side, and the priority privacy setting is
placed in the dynamic form wizard.

The standard form is added to every ticket without option. Extra forms can
be defined and associated with help topics which can additionally be added
to tickets upon creation. This allows for standardization of the dynamic
data location for searches and filtering.

Implemented advanced search for dynamic data. Along with reinstating the
basic ticket search on keywords

Implemented ticket filtering on dynamic data for both keyword searches as
well as searches for special fields (drop-down lists, etc.)

Phone number for users is now completely optional