Show notifycation if the timer was started.
Add notification if timer is stopped.
close timer list if a timer was started.

Recent usage shows that i almost never start 2 different timers. Immediatly
closing the plugin after a timer was started just relieves me of one more
useless keystroke.
Reorder ui to reduce kestrokes to change timer duration

Usage shows that i practically never change a timer except for its
duration/time of execution. This let's me jump immediatly from
"OK"-button to the duration spinbox and back to the "OK".
Press SELECT on the durationspinbox to start the timer

removes one more keystroke to start a timer. It is now possible to press
select while the duration spinbox is selected to start the timer.

Thus it is now possible to open the timer editor, move with one
keystroke ("UP") to the timer duration spinbox, change to the desired
duration and immediatly press "SELECT" to start the timer and leave the
plugin dialogs.
updated readme