Added a JSP servlet for the demo visualizer
Moved some resources around

Updated visualizer to list files
Call plotter.jsp to plot images
Added a method to Plot that stacks multiple images of datasets into one image
Merge branch 'master' of ssh://ibn-sina.cs.umn.edu/project/alexandria08/shadoop-ext into vldb-demo

Conflicts:
	src/edu/umn/cs/spatialHadoop/operations/Plot.java
Merge remote branch 'origin/vldb-demo' into vldb-demo
Changed Plot#combineImages to take Configuration instead of FileSystem in case each file has a different file system
Handle a special case in FileMBR if datafile is not found
Handle the plot command when multiple files are selected
Show spatial join form and update its contents according to selection
Merge branch 'master' into vldb-demo
Run sptaial join on the server from the web interface
Implemented the three optations (RangeQuery, KNN and SpatialJoin) in frontend and backend
Fixed a bug with Plot where the output file is not closed

Implement both plot image and MBR in preprocess
Added a method CommandLineArgument#getColor to be used with Plot
User-defined color to plot files
Use OutputCommitter to stitch images together in Plot
Use OutputComitter with Repartition to concatenate index files
Use OutputCommitter with FileMBR to store resutls back to HDFS

Run FileMBR and Plot in background to allow /preprocess.jsp to return a response immediately

/preprocess.jsp returns rightaway while running the preprocessing jobs in the background
Use OutputCommitter with FileMBR to store resutls back to HDFS

Run FileMBR and Plot in background to allow /preprocess.jsp to return a response immediately

/preprocess.jsp returns rightaway while running the preprocessing jobs in the background