More docs on kw arguments

[KronosTheLate]

I was able to guess that passing the kwarg grid=false turned off the grid. But I am unable to guess the syntax to get fewer grid lines, thinner etc.

It would be AWESOME if the documentation (https://gr-framework.org/julia.html) had a section listing all supported keyword arguments.

[RoyiAvital]

This is really important.
I have no idea how to use the GR.jl functions' parameters.

(I came for the new interactive plot system, so I'm eager to try things.

[RoyiAvital]

For instance, I wanted to show a grayscale image using imshow().
Yet it mapped the pixels by the default colormap.

I could figure it out only by looking at https://github.com/jheinen/GR.jl/blob/master/examples/colormaps.jl and see that "grayscale" is mapped to 2.

Then I guessed the command imshow(mI, colormap = 2);.