Merge remote-tracking branch 'upstream/develop' into develop

* upstream/develop:
  fix for 'cannot access javax.servlet.ServletContextListener'
  Add license header
  Use doubles instead of BigDeciamls for numeric obs values (#120)
  Add version for maven-source-plugin
  - Add HREF enum to HelperValues - Used in GML 3.2.1 encoder return a featurePropertyType with xlink:href instead of an encoded feature, e.g. used to encode sampledFeature in SpatialSamplingFeature
  Remove duplicate casting
  Add support for transactional feature relation (sampledFeature)
  Update XML common version to 2.0.0: - Changed license (Apache License, version 2.0) - Requires Sampling v2.0 decoder changes:   - sampledFeature multiplicity changed from 1..1 to 1..*
removed mandatory schema setting for datasources

(fixes #127)
Merge pull request #129 from autermann/fix/mysql-schema-issue

Removed mandatory schema settings for full DB datasources