[apis] Review of ACTION-146: Update use cases 6 & 7 based on comments.

Hi everyone,

Mr. Hyun and I have worked on ACTION-146: Update use cases 6 & 7 based on comments.
Please see, http://www.w3.org/2011/webtv/wiki/Media_APIs/Use_Cases#6._.22Use_Case_Six_.E2.80.93_Tuner_Control_thru_Web_Application.22

and
http://www.w3.org/2011/webtv/wiki/Media_APIs/Use_Cases#7._.22Use_Case_Seven_.E2.80.93_Channel_Bounded_Applications.22


I believe we have made changes to the discussion we had in the last Media APIs TF teleconference, 2nd October 2013.
If you have any suggestion on the changes, please let us know.

Regards,
Sung Hei Kim