[cliet][test] Add some tests for LatestView
[test][LatestView] Add missing semicolons
[LatestView][test] Add a test for showing an item
[LatestView] Format time values instead of showing unixtime directly
[LatestView] Add units to each values
[LatestView] Translate values to human-readable formats
[client][utils] Remove needless code
[LatestView] Format value string only when the value is number
[client][utils] Rename a function

valueString() ->
formatItemValue()
[test][LatestView] Fix a failed test on TravisCI

Expected timezone is UTC on TravisCI.
[OverviewItems] Translate values to human-readable formats
[client][util] Simplify formatMetricPrefix()
[client][utils] Don't allow negative pow in formatMetricPrefix()
[test][OverviewItems] Add a test
[OverviewItems] Add a test for building the table
Merge pull request #749 from project-hatohol/format-item-values

Format item values