#33 is_attenting method was added to DoctorUser class. This method return bool value:  true if exist processing appointments and false else.
#33 start_appointment and finish_appointment methods were added to DoctorUser class.
#33 Start appointment button and it's handler were added to all_appointments.js.coffee.  Start appointment functional was added to /cabinet/doctor/appointment_controller.
#33 Fix: start appointment link-button is rendered for appointment with status 'busy' only.
#33 It was added appointment starting and stopping control system. If user started two and more appointments or appointment was started no busy status or  one was stopped no process status, will be exception thrown.
#33 Page reload invoking was added to all_appointments.js.coffee. Refreshing would be  occurred if start_appointment() returned success status.
#33 It was added the processing appointment button.