Solution conventions

Move js file into js folder. Remove unused variable. Tweak variable names to be more readable. Fix indentations. Cleanup logic in isItSweepingTime method
Use UTC

API will pass UTC datetimes, convert all date time comparisons.
Clean up

Update naming to match conventions. Tweak d3 to avoid selecting the sam dom object multiple times
Merge branch 'standardize-date-and-times'