Multi-Process Build and Scan Fixes

Enhancements:

• Add ability to circumvent prohibition against scans running for > 30 minutes on Android N.
  (#529, David G. Young)
• Add support for running the beacon scanning service in a separate process and working with
  application setups that have more than one process. (#479, David G. Young)

Bug Fixes:

• Fix Google Play submission errors by no longer using uses-permission-sdk-23 in
  Manifest (#527, David G. Young)
• Fix failure to restart scanning in some cases after bluetooth has been off but then is turned
  back on. (#519, David G. Young)
• Fix failure to stop scanning when unbinding from service or when the between scan period
  is nonzero. (#507, David G. Young)
• Fix possible NullPointerException with BackgroundPowerSaver on devices
  prior to Android 4.3 Jelly Bean MR 2 (API 18) (#516, Aaron Kromer)
• Fix rare edge case causing NoSuchElementException when using the legacy
  BeaconManager#getMonitoringNotifier and BeaconManager#getRangingNotifier
  where the notifier sets were modified external to BeaconManager by another
  thread (#516, Aaron Kromer)
• Fix inability to use RunningAverageRssiFilter.setSampleExpirationMilliseconds(...) (#523,
  David G. Young)