Mms: Add basic mark as read feature

this will add "Read" button to mms notification:
https://lh4.googleusercontent.com/-sTdsJFAEoiA/UZ4g-VIq53I/AAAAAAAAEhM/sMTrRS4gQzI/w378-h672-no/Screenshot_2013-05-23-15-36-44-.png

Note: It will only show on single threads

Signed-off-by: DvTonder <david.vantonder@gmail.com>