new daily chart x-axis with sticky label on left

Note that this PR include adding moment as a tideline dependency (solely for formatting the ordinal 'th' etc. at the end of the date strings - d3's time formatting functions don't do this, unfortunately). This will be *temporary* but I don't want to hold up this PR with the refactoring that needs to be done to pull out all of tideline's datetime functions, add them to sundial, and give tideline a sundial dependency.

Ready for merge after a review.
yay - no magic numbers :) even though this has been there for a while