[AudioSystem][IVI]: Implementation of Tizen Audio System/Control API.

This commit implements proposed Tizen System Volume API on xwalk:
  https://wiki.tizen.org/wiki/User:Tanuk/AudioSystemAPI
This commit also includes a demo application that demonstrates the
usage of the api.

This enables to write volume control/settings/mixer type of web applications
using xwalk.

BUG=XWALK-1330
I don't think a memory leak here, the if condition makes sure that no element exists with given key. so there is no chance of assigning new pointer to existing key in the map, same for all other. Do you agree?