Even more weather related data

for RWIS-systems, the following new attributes can be useful:

• Wind: maximumWindDirectionBearing
• PointByCoordinates: altitude
• MeasurementSpecificCharacteristics: altitude (for single measurements)

There are even more specific enumerations (new ones and extending existing ones). It can be discussed whether to insert them into level A or not:

• precipitationIntensityGrading: {noPhenomena, light, moderate, heavy, violent, severe}
• precipitationType - see picture
• weatherRelatedRoadcondition: add literals {+moist, +rime, +snow(!), +glaze, +notDry}
• TemperatureBelowRoadSurface - depthBelowRoadSurface < already covered by issue #101
• measurementEquipementLocationType - see picture
• measurementSiteConstructionType - see picture
• measurementSiteRecordType - see picture
• temperatureSensorPosition - see picture
• SiteMeasurements: statusType - see picture
• SiteMeasurements: qualityInformation - see picture

All elements mentioned (including their literals) are visible in the attached pdf. It's part of a level B extension. I will prepare the documentation and provide the complete extension as soon as possible.