Easy remove gridlines

[thomas-neitmann]

Easily remove grid lines, as discussed in #31.

[jonocarroll]

Thank you! I'll work through the changes soon. I like the idea of abstracting out the teach argument but I want to carefully check some edge-cases.

[jonocarroll]

Sorry, I got distracted from this but I'm having a closer look now. I have some suggestions I'm going to try to push to your branch.

Also, FYI,

Warning message:
`ctxt_frame()` is deprecated as of rlang 0.3.0.

[thomas-neitmann]

Thanks a lot for merging into master @jonocarroll!

In the meantime I thought of a slightly different interface for the functions. What do you think of

easy_remove_gridlines <- function(which = "XYxy")
easy_remove_x_gridlines <- function(which = "Xx")
easy_remove_y_gridlines <- function(which = "Yy")

Upper and lowercase letters would indicate major and minor gridlines, respectively. I've implement it like this for the themes in {ggcharts} here.

I feel this is a much cleaner and easier to use interface. What do you think?

[jonocarroll]

I've been meaning to merge this for far too long. Thank you again for the contribution!