fix boxplot behavior when only y values are provided

[ValdarT]

This fixes the behavior of boxplot() when user only provides y values. Related to discussion in #56

I hope it's not too much of a hack.

Some quick tests:

boxplot(rand(10))

boxplot(rand(10,2))

boxplot(["a" "b"], rand(10,2))

boxplot([:c :d], rand(10,2))

boxplot(3:4, rand(10,2))

boxplot([3 4], rand(10,2))

boxplot([0.5 4], rand(10,2))

boxplot(rand(["a", "b"], 20), rand(20))

boxplot([rand(["a", "b"], 20) rand(["c", "d"], 20)], rand(20,2))

boxplot([rand([:a, :b], 20) rand([:c, :d], 20)], rand(20,2))

[mkborregaard]

Hi, thanks - I guess this could also be applied to violin? I suggest you take out the second bit though.

[mkborregaard]

x values do not need to be categories - x values can be used to specify the position on the x axis as well.

[mkborregaard]

looks good

[ValdarT]

Thanks for the quick reply! Sure, makes sense. Applied the changes.

[mkborregaard]

Thanks a lot @ValdarT !