add local version of BTreeSet
pass the simple test
pass load and save test
fix the union and intersect test
Merge remote-tracking branch 'github/genomix/fullstack_genomix' into jianfeng/node-store-in-hdfs
update BTree API
add ExternalableTreeSet
add test for ExternalSet
wbiesing/ray-genomix-refactor
not compilable ? fix the node
change all the usage of ReadHeadSet
temporary test
using abstract class to avoid hdfs generic class parsing problem
merge with master
make the genomix-hyracks test passed
make genomix-hadoop test passed
make default bubble max dissimilarity 5% instead of 50% (same as contrail)
update by code review
change some namings
merge with master