make default bubble max dissimilarity 5% instead of 50% (same as contrail)
merge with master
Merge pull request #86 from uci-cbcl/jianfeng/node-store-in-hdfs

Jianfeng/node store in hdfs
add max length to simple bubbles
improve error message for buildgraph format failures
Merge pull request #87 from uci-cbcl/wbiesing/bubble-merge-uses-max-distance

bubble merge uses max distance
fix bug where tip with search stored the internalKmers rather than the ids
Merge pull request #90 from uci-cbcl/wbiesing/bugfix-for-tip-remove-with-search

fix bug where tip with search stored the internalKmers rather than the ids
modify the iterator in RayScaffolding into range Search