Issues with datatype Any

[mjacoby]

This issue has already been submitted as change request and is just posted here to have a central place where all the issues can be found

SensorThings API introduces the datatype Any for some entity properties (namely Sensor.metadata, Location.location, Observation.result, FeatureOfInterest.feature) which can take any value specified in JSON. This raises two issues:

• How are these values stored? Should the JSON datatype be preserved when inserting a property of datatype Any (e.g. when inserted as JSON Number can it be expected that it will be stored and returned as JSON Number)?
• Semantics of some operators are undefined when used on properties of type Any
  • $orderby clauses on properties of type Any
  • built-in filter operation using properties of type Any as operand
  • built-in query function using properties of type Any as parameter

For the detailed description please see the change request 383

[hylkevds]

I've reworked the changes for this issue into a specific branch:
https://github.com/hylkevds/SensorThingsAPI/compare/master...dataTypes