added sample grid implementation
Merge remote-tracking branch 'origin/master'
gitignore update
Merge https://github.com/bjoernlohrmann/stratosphere-workshop-template
added and tested Grid
Added udf for intersecter
bounding box
Merge branch 'bjoern'
Merge https://github.com/komoot/stratosphere-workshop-template
modified schema
Added a PactList implementation.
Merge https://github.com/schernic/stratosphere-workshop-template
Implemented the Gridify operator.