switch to guavas padding function
added todo
added tests for milli formating
switched to timeunit
Merge branch 'master' into util-delegete
revert back to using time constants
updated todo msg
Merge branch 'master' into util-delegete
Merge branch 'master' into util-delegete
Merge branch 'master' into util-delegete
reject negative time values for convert ms
removed addLeadingZero in favor of guavas Strings.padStart
Merge branch 'master' into util-delegete
Add comments to some classes in tachyon.master

Add comments to some classes in the package tachyon.master, for more
detailed java doc.
Comment more about DependencyType

Describe more information about each type of dependency.
Merge branch 'master' into util-delegete
Merge pull request #290 from dcapwell/util-delegete

Util delegete
Merge pull request #302 from PasaLab/comments

Add comments to some classes in tachyon.master, for more detailed java doc.
improve doc
tweak doc