- Lab 2 - Macro Messages:
  - For this lab we will extend the `msglab1` macro written for the previous lab.
  - Copy of the `msglab1.mm` to `msglab2.mm`. The use `UPDATE` to add the new macro to the TRAIN option tree.
  - This lab will not use a `FEATURE` so delete the line creating the feature and delete the part of `processMessage` where you set the position of the feature. (Do not delete the check for the "MARK" message, you will be using it again.)
  - This time when you get a mark message you are going to send a "ZOOM" message to the plot and zoom it in by 50% (e.g. if the current width is 360° the new width will be 180° centered on the point the user clicked).
    - You can get the current bounds from the plot using:

          res reg.myplot.x1
          res reg.myplot.x2
          res reg.myplot.y1
          res reg.myplot.y2

    - If you check out the explain file for `PLOT`, you will see that it takes in a "ZOOM" message with the data set to `{XMIN=,XMAX=,YMIN=,YMAX=}`. This is the message you will need to send to the `PLOT` (note that you can use `INFO=0`).
    - You will need to compute the new bounds for the `PLOT`. It should be half the width and height of the current plot and should be centered on the point specified in the data of the "MARK" message.
  - Try running the macro and notice what happens when you click and unzoom.