add axis and title labels to chart

2018-09-24-temp-by-month-7.md

add axis and title labels to chart

Example X axis for Dog Sled Expedition Chart

X axis labels were covered on September 6, 2018.

Example for Dog Sled Expedition Chart Y axis

Y axis labels were covered on September 10, 2018.

svg.append("g")
    .attr("class", "yTitle")
    .append("text")
        .text("Number of Dogs")
        .attr("text-anchor", "middle")
        .attr("x", -40)
        .attr("y", height/2)
        .attr("transform", "rotate(-90, -40," + height/2 + ")");