Android : Add bigview support

Hi, 

I did a small evolution to have a new feature on android, be able to display the notification as a big view: 
http://developer.android.com/training/notify-user/expanded.html

To activate the option, you need to pass this new option when creating a notification:

    notif.bigview = “true” 

Unfortunately i wasn’t able to use a proper boolean, when i do so, the options.optBoolean in the Options.java doesn’t get the true value, i don’t know why, you may be able to fix it.

Anyway, feel free to comment i can change some stuff.

Thibault