Will close #96.

Yesterday I took a long walk with this changed version of Trackbook and was happy with the results. The points were recorded about twice as frequently as normal without decreasing the track quality or rest detection.

Note!! In the future, I think we should modify isAccurateEnough to increase the confidence that we are below the user's set threshold. Like this:

         when (location.provider) {
-            LocationManager.GPS_PROVIDER -> isAccurate = location.accuracy < locationAccuracyThreshold
+            LocationManager.GPS_PROVIDER -> isAccurate = (location.accuracy * 2) < locationAccuracyThreshold
             else -> isAccurate = location.accuracy < locationAccuracyThreshold + 10 // a bit more relaxed when location comes from network provider
         }

However, I did not do that in this pull request because any user who has already tuned their accuracy threshold setting will suddenly find that their tracks are recording fewer points after updating. Increasing confidence decreases tracking interval. I don't want to make that change without further careful consideration. Likewise, we can do accuracyDelta * 2 (or even just 1.5, etc.) if we want to increase the confidence in distance deltas.

One more note: If we're going to keep the waypoint interval at 1s, perhaps we should merge that function with MapFragment.kt's periodicLocationRequestRunnable which also runs at 1s. At the moment, this pull request keeps them as separate timers, which is probably a bit wasteful.

Thank you @y20k and @Hob111.