remove two-week day-axis tick lines
adjust axisGutter for when no tick lines
add month to day ticks with dot separator
add month to day ticks with dash separator
add abbreviated month name to day ticks
Merge branch 'jebeck/no-tick-lines-two-week' into jebeck/no-tick-lines-text-month
re-embiggen axisGutter to make room for abbreviated month names
Merge pull request #53 from tidepool-org/jebeck/no-tick-lines-text-month

better ticks for day axis in two-week view, distinguish weekend days