[tests] Keep display on during testing

Signed-off-by: Matti Kosola <matti.kosola@jolla.com>
[tests] Change tests.xml feature to nemo-qml-plugin-time

Signed-off-by: Matti Kosola <matti.kosola@jolla.com>
Merge pull request #9 from mkosola/master

Keep display on during testing