Non-Constant Intervals on Some Devices

[fennifith]

There might be a small delay loading the sound (shouldn't it already be in memory?) that causes the beats to become... unstable. Fix: try using [Handler.postAtTime](https://developer.android.com/reference/android/os/Handler.html#postAtTime(java.lang.Runnable, long)) instead of whatever I'm currently doing. That or a TimerTask. Unfortunately, I do not own one of the affected devices so this will be difficult to test.

[rsalameh]

I'm having a related issue with the app on my Polar M600 smartwatch running Android Wear 2.7.0.178645119.

Specifically, Metronome does not consistently vibrate at the user-configured bpm. This happens when the smartwatch screen dims or its not in the foreground. It stops vibrating and then haphazardly will vibrate thereafter. It some cases it will do one long vibrate, so-to-speak.

[theaquarium]

You can test it with an Android emulator.