Use istream::exceptions to report illegal file format
Support new data format of jubatus 0.5: fix #2
Use jubatus::util instead of pficommon to remove dependency to pficommon
Remove redundant include
Merge pull request #3 from jubatus/new-format

Support new data format of jubatus 0.5: fix #2
Merge branch 'master' into develop
Fix readme
Merge branch 'release/0.5.0'