change the symbol name related to the voutput

change the symbol name related to the voutput

1. The voutput is created at the tdm_display, so it belongs to the tdm_display.
The creation of the voutput should be done at the display.
2. The voutput should be distinguished from the output. The functions associated
with the voutput has to get the voutput symbol name.

Change-Id: Ie21def171a1e8d9c43150e23347542c3a232db23