Fix the random result bug. The root cause is I used hasCode in the
compareTo function of the ReduceEvent class. Therefore, the compare
result is kind of random from different runs.

modified:   Java/src/coho/geom/twodim/ops/OutwardReduce.java
modified:   example/cav14/run_dpll.m
Merge /ubc/cs/home/c/chaoyan/cra