Usage: $this->user->Faculty->ID or $this->user->Faculty->getDisciplines()

* Moved some static methods to Factory model
* Removed unused param $teacherID
* Assertion checks moved to models

Use RusLang::tr() function instead.

Field Model_Factory::ID came public, new method getStudents() added.
Renamed Model_Students::searchStudents() to search(); removed duplicate method NotAttendingDiscipline().

– Type constants (exam, credit)
– New function exists()
– More clear method names

1) fix Rating Model
2) sql CreateSubject: restore expected behavior (see todo in commit "Refactoring of subjects upload page" 19.06.15)
3) refactor and disable JavaAuth (see todo)

Not all servers detect HTTP_X_REQUESTED_WITH header.
And now it is possible to load excel files.

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.

Also renamed $id_name to $ID_FIELD + documentary comments