todo

swarm的例子,包換對java,xml,servlet等的介紹

o  compare it to using the JNI-accessible plotter and Raster.
o  compare it to using normal Java2D graphics
o  put in the optimization for raster spaces and compare
o  find the raster artifact bug
o  finish exception handling machinery to look like Prisoner.java
o  revert to Benedikt's original space data structure and compare
o  comment and prettify
o  add ModelSwarm to jipd-grid.scm