Feature :: Advanced Search 2.0

**This PR REQUIRES multilingual phase III and should be rebased after it is merged**

### Summary
This introduces the next evolution of the searching system for osTicket. Basic overview of new stuff includes

  * ORM based query engine
    * Most models have been upgraded to use the ORM rather than raw SQL
  * Searching now possible on any/all fields
    * Basic Ticket, User, and Organization data
    * Custom data for Ticket, User, and Organization
    * Keyword search for ticket and ticket thread data
    * [x] Fields on extra custom forms attached to tickets
  * Saved search support
    * Save and recall your popular searches
    * [ ] Share searches with other members (requires administrative role)
  * [ ] Create a (public) queue from and advanced search
  * [x] Current search shows up as a separate, sticky queue

### Outstanding
  * [ ] Reimplement export for user and organization directory pages
  * [ ] Advanced search for users an organizations
  * [ ] Add/move the rest of the ticket basic fields to the drop down list (flags for instance)
  * [x] Add and manage `effective_date` to ticket table
  * [x] Add and manage `est_duedate` to ticket table
  * [x] Reimplement "hide answered tickets on open queue" option

### Screenshots
![screen shot 2014-11-28 at 9 24 12 pm](https://cloud.githubusercontent.com/assets/672074/5233423/58e40e66-7746-11e4-8e1e-1d48b967ca44.png)
New look and feel, plus extended options on searching based on the field type

![screen shot 2014-11-28 at 9 26 05 pm](https://cloud.githubusercontent.com/assets/672074/5233425/836b26f6-7746-11e4-9968-296d54bdabde.png)
Search custom data, again with flexible searching options

![screen shot 2014-11-28 at 9 26 34 pm](https://cloud.githubusercontent.com/assets/672074/5233426/ac44c442-7746-11e4-9eca-202128c3a082.png)
Advanced search is now sticky, so returning to the ticket queue page no longer drops the search

![screen shot 2014-11-28 at 9 40 01 pm](https://cloud.githubusercontent.com/assets/672074/5233432/4b310d40-7747-11e4-9dc0-d76cc294a2fb.png)
Search for just about anything