v0.1,   2012-11-03 -- Initial release.
v1.0,   2013-05-19 -- Adapted to new API structure.  Functionality extended.
v1.1,   2013-08-12 -- Compatibility with Python 2.x added.
v1.2,   2013-12-04 -- Added parsing of site elevation and improved versatility
		      in finding nearest sites to given coordinates.
v1.3.1, 2014-06-15 -- parse_val can now accept returned data with single timesteps such
		      as when a forecast has been requested using the isotime parameter.
		      _query method of MetOffer class now returns raw API output.  Methods
		      which use this handle conversion from json to Pythonic objects.
		      Tuples in the data attribute of Weather instances returned by
		      parse_val are now 3-tuples (EXCEPT for 'timestamp').  The
		      third element is the 'name' of the measurement type as
		      used by the API (e.g. 'T' for 'Temperature').
		      Separate function created to devise dict that maps Met Office
		      'names' to description and measurement unit from the raw returned
		      data (extract_data_key).
