Use MapQuest OSM tiles instead of Mapnik

Members of OSM recommended making use of the free MapQuest tiles
instead of leaning on the mapnik infrastructure.  More information
available at:

http://developer.mapquest.com/web/products/open/map
Move CoverageOverlay to its own class
When zooming greater than the tile provider's ability, scale the upper zoom layer
Better ensure that each tile gets drawn only once

Use a set to keep track of what has been drawn.  This isn't efficient, and
could use some refinement.
Merge pull request #770 from keverets/mapquestosm

Use MapQuest OSM tiles instead of Mapnik
Merge pull request #769 from keverets/coverage-overlay-zoom

Coverage overlay zoom
Make default zoom 16 rather than 13
Include new logos

Taken from https://github.com/mozilla/ichnaea/tree/master/ichnaea/content/static/images
Merge pull request #776 from keverets/new-icon

Include new logos (@keverets)
Merge pull request #775 from keverets/higher-default-zoom

Make default zoom 16 rather than 13
removed EOL whitespace
See Fennec integration bug https://bugzilla.mozilla.org/show_bug.cgi?id=1038843

- Refactored StumblerService, moved bound usage to ClientStumblerService,
this is not used by Fennec.
- Restructure code by thread. Concurrency bugs are the highest-risk, and
the code can be clearly organized by thread so future contributers can
see at a glance where thread divisions are.
- ensure that stumbler service init() happens on the correct thread, in
MozStumbler, this is the main thread, in the Fennec service, this is on
the service's dedicated thread
- remove the use of the blocklists from Fennec.
- changed uploading in fennec mode to only upload after a start intent.
Need to ensure that when foregrounded, Fennec sends this message.
Merge pull request #784 from garvankeeley/squash-fennec-changes

Refactor for Fennec Integration
reworked the code from #761 to be rebased ontop of the fennec code
standard changes
added license headers to all java source
Clarified the TurnOffReceiver to send an intent to pause scanning instead of toggling the scan.
Merge pull request #782 from crankycoder/features/761-stop-notification

fix stop scanning button in the Notification pulldown
Translate new string to spanish
Create client side prefs that extend the service prefs.
setLastMapCenter in onDestroy as well as onSaveInstanceState, no harm in
the extra call, and without it, I get cases where the last XY isn't set.