data viz updates

[carriewright11]

• adding a slide before tips to show that we are now talking about tips and common issues might be good
• maybe we can remove the linetype from the plots until we get to introducing it
• mention ThemePark maybe in the lecture
• revisit slide before axis limits with xlim() and ylim()- do we need that there now?
• add a tip that you need to run the name of your plot to see it - someone got confused about this
• add that you can use numbers for linetype too

Lab

• add themepark to show fun themes :) https://matthewbjane.com/ThemePark/ - need to tell people how to install
• add tip about using theme(legend.position = "none") for the last bonus in the lab - not sure what my last issue was saying about this- maybe I had already fixed it but I think a bigger tip might be helpful. or actually maybe it is best to leave it out but provide tips on how to find the documentation to figure it out
• for final question (not bonus) see what facet looks like with and without geom_point() - should lose a value for one of the facets and it will be empty

[carriewright11]

• explain what groups are doing some more in the lecture - splitting up a line where multiple values are being plotted etc.

[avahoffman]

• get rid of mapping= aes.. throughout? We weren't using it consistently

[cansavvy]

I've addressed all the issues here in #544 Except for these two points because I'm not exactly sure what they mean.

Can you give me more context/point me to what part your referring to?

• for final question (not bonus) see what facet looks like with and without geom_point() - should lose a value for one of the facets and it will be empty
• explain what groups are doing some more in the lecture - splitting up a line where multiple values are being plotted etc.