As reported in #510, axis titles can be positioned improperly depending on the size of the plot. In a2aedac, axis titles were changed to annotations, so they are not duplicated and work much more similarly to ggplot2. Unfortunately, plotly annotations are positioned based on a [0,1] scale with respect to the plot area. This means the axis titles scale inversely and negatively to the plot size. When the plot is small, the x axis title will be placed too high. When the plot is large/high, the x axis title moves too far down sometimes out of the svg bounding box.

This pull changes to use plotly axis titles when the plot is not facetted. When the plot is facetted, the plotly axis titles are changed to "" in favor of the annotation approach.