Remove logging; set service to foreground service & modify notification call to accommodate foreground service
Add deleteTracklogs() ready for multiple deletes from tracklog list
1) Remove onRestoreInstanceState() and onSaveInstanceState() in favour of shared pref
2) Provide shared pref for indicating whether tracklog recording in progress
3) Change onCreateOptionsMenu() to onPrepareOptionsMenu(), so menu can be updated each time it is displayed, not only on menu creation
Change calls to getApplicationContext() in service intent creation back to reference this (the activity)