Support big vertex in Pregelix.
--For those vertice beyond page size, we store them on HDFS as immutable files.
--Updates on those big vertice will trigger creations of new immutable files.

Change-Id: I6b6f0528b6b5360c96dcdace1fa360d42c517f22
Reviewed-on: http://fulliautomatix.ics.uci.edu:8443/72
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Pouria Pirzadeh <pouria.pirzadeh@gmail.com>
diff --git a/pregelix/pregelix-example/src/test/resources/expected/skew/part-0 b/pregelix/pregelix-example/src/test/resources/expected/skew/part-0
new file mode 100755
index 0000000..c2c0cc0
--- /dev/null
+++ b/pregelix/pregelix-example/src/test/resources/expected/skew/part-0
@@ -0,0 +1,6 @@
+1	0.1538057869748262
+5	0.021540394083972653
+9	0.008851770565007962
+13	0.08308297649373161
+17	0.012504121497877515
+21	0.009166666666666667