Fixed a bug with RandomSpatialGenerator that generates zero width or height rectangles

Fixed a bug with skipping the first line in a block in SpatialRecordReader
Handle a special case when a line end is perfectly aligned with a block boundary
Added some comments to the versions files
Fixed a bug with KNN that generates duplicates in results
Fixed a bug with RTree#knn that causes all results to be the same

Added a function RTree#findBestDegree that finds the best degree to store an RTree in a fixed size
Improved the calculation of RTree#findBestDegree about 7 times
Use a new technique to write R-tree blocks (local indexes) that compacts its size to ensure fitting an HDFS block
Added a LOG entry indicating used degree for RTree
Fixed a bug with SpatialRecordReader#nextShapes that causes the millionth record to be skipped
Changed ReadFile to write also the range of each block [start, length]
Improved DistributedJoin to ensure answer pairs are in the same ordering of input files
Check for input file existence in all operations