NF+TST: added tools to convert different formats of partition.index, partition.community for refactor of code
RF added contains_only to reduce repetition, simplify code based on @stefanv suggestions
Fix typo. Slightly more explicit exception checking in _contains_only.
Merge pull request #18 from cindeem/add_util

NF+TST: conversion tools for refactor of GraphPartition
Merge branch 'master' of https://github.com/fperez/brainx