explore usage of O&M V3 Observation Characteristics for encoding of rangeType

[KathiSchleidt]

Observation encoding with DataArray and DataRecord available from
https://www.dropbox.com/s/f6hdunciczs65wm/160701_OM_Observation.xml?dl=0

[KathiSchleidt]

related to #3 and #1
Also - not sure where to put this info, but the stable ISO UML is available from https://github.com/ISO-TC211/HMMG/tree/master/EA