Charts with dates should reflect time linearly

Currently the only option to display data over time is to use a line chart. This works fine if data are collected every day, but if data are missing on a certain day Knack will input a 0 into visualizations. If you select "hide empty groups", this day will be removed from the x-axis, thus a break in data of 1 day will appear exactly as long as a break in data of 1 year. This should be fixed such that the x-axis for dates is continuous.