PolarAxis not supported

[marcpabst]

Bug description

PolarAxis is not supported.

Steps to reproduce

Running

AlgebraOfGraphics.draw(plt, axis=(type=PolarAxis, thetalimits=(-pi, pi)))

results in

MethodError: Cannot `convert` an object of type 
  Type{PolarAxis} to an object of type 
  Union{Type{Axis}, Type{Axis3}}

Changing this struct to include Type{PolarAxis} should fix the problem, but needs testing:

AlgebraOfGraphics.jl/src/entries.jl

Lines 31 to 35 in 7c143ee

	struct AxisSpec
	type::Union{Type{Axis}, Type{Axis3}}
	position::Tuple{Int,Int}
	attributes::NamedArguments
	end

Edit: Adding PolarAxis is apparently not enough, results in

MethodError: no method matching initialize_block!(::PolarAxis; zlabel::String, zticks::MakieCore.Automatic, ylabel::String, xlabel::String, xticks::MakieCore.Automatic, yticks::MakieCore.Automatic)

Btw: I really like AoG!

[marcpabst]

I got it to work by omitting all of the arguments to PolarAxis that cause problems - but can anyone point me to the code wherexticks, xticks, xlabels etc are actually added to the axis tuple? Would be happy to properly fix this! Maybe @SimonDanisch or @piever?

[jkrumbiegel]

It's a bit hidden but the symbols are assembled here

AlgebraOfGraphics.jl/src/algebra/layers.jl

Lines 303 to 304 in 9b1b385

	for (k, v) in pairs((label=label, ticks=ticks(scale)))
	keyword = Symbol(var, k)

and would have to be adjusted for PolarAxis