updated CORS filter
allow any request header for CORS requests
Merge branch 'dev' into fix/cors-supported-headers

* dev:
  remove provided export.properties
  make test for shapefile encoding independent from db state
  adjust exception to provide the count of the actual track
  add image for docs
  fix bugs in markdown file
  add R example and some more headlines to additional encodings documentation
  Added information about limit for shapefile...
  Changes according to discussion:...
  Fixed tests
  Corrected c&p mistake
  Created tests for shapefile export
  Implmenented check for too long tracks...
  Added exception for tracks that are too long...
Merge pull request #200 from autermann/fix/cors-supported-headers

Fixed CORS supportedHeaders