remove hardcoded t=0.0, make it possible for app to pass in a start second parameter

I have tried on lg/roku/chromecast, there is no need to specify t=0.0, by default it is 0.0.

If not hardcoded, it will allow the application to specify a start time (e.g. "<YOUTBEID>&t=1234"). My app is currently using that feature: user can watch a video on their phone for a while, then switch to big screen, user will not want to start from beginning after the switch. 

I have not tested on samsung, but this commit left pairingCode untouched and hopefully it will not break anything. Actually I do have a question for samsung. I have a samsung 2013 model, DIAL never works for youtube app, and there is no no official document on that. Are you able to get it to working? Is it for 2014 model only?  Thanks.