junit test for tachyon.Pair
improve UserInfoTest
image write utilis.
test all combination of defined pairs
Merge pull request #43 from cybermaster/master

more tests.
add util to i/o buf.
image, and write edit log
update java version to 1.7
add editlog load
test journal
remove kryo
Merge branch 'master' of github.com:amplab/tachyon
remove LogType
various fixes, examples, run scripts
fix sync in edit log
add transactionid
add flushed transaction id and the api to get it.