Add additional slicing possibilities for line graphs

It would be very helpful in some cases to have additional ways to split data in line graphs. Here are a couple examples:

• A "Shade By" option that works in conjunction with the "Color By" option. So you could have a categorical column selected for "Color By" and then if you had multiple lines associated with the category you could have each of those made distinct by how dark the line is.

• A "Line Style By" option - similar to the "Shade By" option above but allows you to alter the thickness and dash style of the line.

Both of these ideas would work best for categorical data but may have applications for non-categorical data as well.