title: Timers(setInterval) in ionic apps go to sleep after some time in the background
body: <p>My ionic app has a timer(a simple setInterval that ticks every second) which works perfectly fine when the app is in the foreground. However when the app goes to the background and comes back to the foreground after 10 minutes, the time displayed in the app is wrong (the time is much less that it should be). I have tried adding the timer into a directive and also using the native DOM manipulation api(document.getElementById, etc) methods, but they both didn't work. I think the ionic framework is doing something to the view and bindings when the app goes to the background. Has anyone experience such a issue and if so how did you guys manage to fix it?</p>