remove separator insets
new design updates to DaySection header, thanks to Tam
remove more separator insets
remove separator insets. make height shorter
major refactoring of Time to build appropriate responses from getRelativeDateStringForEpochTime. This method has gotten so specific to DaySectionHeaderCell that I may want to refactor it there in the future. Lots of *fun* date math in here, calculating the coming Saturday & Monday & next month & next year.