plugins: shell: notifications: add support to close a notification by app name

Signed-off-by: Simon Busch <morphis@gravedo.de>
plugins: compositor: check for qt > 5.2.1

We didn't changed qtwayland to API version 5.2.1 when we switched to qt 5.2.1 so we have to
check a little bit more carefully to use the correct API.

Signed-off-by: Simon Busch <morphis@gravedo.de>
plugins: common: expose application id as property

Signed-off-by: Simon Busch <morphis@gravedo.de>
Merge pull request #75 from webOS-ports/morphis/notification-by-name

Morphis/notification by name