* Fixed bug with students search
* Documentation for Model_Student
* Utility function Arr::groupBy()

Simplified methods. If you want to group elements by any key, write ->as_array('key').

Separated logic and representation, removed unused functions, duplicates

1) exam page: hide hidden div with ( json data )
2) update session info on profile/settings changes (User.php)
3) fix profile page model ( Model_Teacher )
4) fix change discipline's control type ( sql )
5) fix sql response in bind group ( repeated binding problem )

Default faculty was not defined by default.

Russian constants are moved to twig & RusLang modules.
Functions were renamed to Semesters::load($id) & Semesters::loadAll().

* Model User has constants to check access for pages
* Some routes are moved to separate files (app/routes/api)
* New abstract model Container for complex objects like Discipline & Student (with -> access operator)
* New DeanOffice controller with access checks
* New SQL procedure to get info about students
* Profile page for students (/dean_office/students/127)

+ Code refactoring in the AdmStudent controller