Added a time series service, which provides a ZeroFilled class, setup the histogram to use it so that zero measurements will be displayed
created timeSeries service with a ZeroFilled class to manage the rows for the histogram
moved the timeSeries service into the histogram module.
Merge branch 'zero-filled-ts'

Conflicts:
	js/services.js
Merge pull request #400 from spenceralger/master

Creates zero-filled data for the histogram.