support for writing RDF
small user model example
Merge branch 'dev' into lod

* dev: (67 commits)
  include unit in statistics (fixes #56)
  purged measurement activities (fixes #55)
  fixed track bulk upload with only a sensor referenced in the track
  added validation for "date" format (closes 51)
  adjusted user schema
  fixed typo
  fixed request schema validation
  addtional user profile attributes
  sort tracks by recently modified (fixes #54)
  unified track/measurment creation (sensor reference)
  removed unnecessary type literal
  do not modify query parameters
  generic filters for sensor attributes (closes #42)
  abilitiy to parse arbitrary sensor properties
  allow arbitrary maps as sensor properties
  filter sensors by type (see #42)
  removed obsolete classes
  remodeled sensors close #47
  remodeled sensor
  throw 409 for already existing mail addresses (fixes #52)
  ...

Conflicts:
	pom.xml
	rest/pom.xml
	rest/src/main/java/io/car/server/rest/MediaTypes.java
	rest/src/main/java/io/car/server/rest/encoding/GroupEncoder.java
	rest/src/main/java/io/car/server/rest/encoding/MeasurementEncoder.java
	rest/src/main/java/io/car/server/rest/encoding/PhenomenonEncoder.java
	rest/src/main/java/io/car/server/rest/encoding/SensorEncoder.java
	rest/src/main/java/io/car/server/rest/encoding/SensorsEncoder.java
	rest/src/main/java/io/car/server/rest/encoding/TrackEncoder.java
	rest/src/main/java/io/car/server/rest/encoding/UserEncoder.java
Merge branch 'dev' into lod

* dev:
  switched deployments to https
  Activity stream of friends (fixes #57)
  fixed user/gender update issue
ported exisiting restrictions to new model
cache access checks
more fine grained rights
more fine grained rights
more fine grained rights
added rights to abstract encoder
enforce rights while encoding groups
enforce rights while encoding users
missing rights implementations
fixed NPE for not anonymous users
more fine grained access rights
enforce rights while encoding tracks
enforce access restrictions in resources
Merge branch 'dev' into rights

* dev:
  fixed 500 ISE when not submitting any entity
  fixed invalid sensor creation schema
anonymize measurements
do no anonymize sensors