Looks like there are battery drainage issues with the current half-done
implementation, so add option to turn it off. Only takes effect on
restart, and only matters on dbg variant now since it's compile-time
disabled on the main variant.
Also add discovery machine state to ConnState printout, stop running the
machine over and over (likely the battery problem), but add ability to
restart it triggered by the ConnState's "reconnect" button.
Also start persisting the most recently seen set of peers. If service
discovery and not connecting is the problem having these available to
try to connect to on startup might help.
Merging of AndroidManifest.xml files meant the dbg flavor was getting
its C2D_MESSAGE permission and the main flavor's, which on recent OS
versions meant it couldn't be installed. Use substitution from gradle to
fix.
