#8 Modified isNetworkOnline to be more understandable
#8 Added a method to check whether a wifi connection is available

isWifiOnline() checks if wifi is available.  This is used in
conjunction with isNetworkOnline to ensure that an internet connection
is available before a feature is added to the online feature service.
Added toast message if sd card not available to save output file
Updated README  file
Added a showOutput method

Added a showOutput method to control when output is shown and to have a
single method controlling toast output for the library.
#9 #8 Bolstered error checking and associated output messages

Fixed the methods to check whether the network and wifi are online
Added additional output messages when connections are/aren’t available
and points are/aren’t being saved
Removed debugging toast messages from PositionTracker constructor
#10 Clarified output messages and changed when output file is created

The output file is now created in the initializeOutputFile method so
the output file object is only created once.
Merge branch 'dev'