Hello everyone, I was planning to use VonMisesFisher distribution for some modelling purpose like random walk. But when I tried to sample vectors for k=0 which should be giving values following uniform distribution, function gives error.

Is there some other function for uniform sphere distribution?

```
ERROR: κ must be positive.
Stacktrace:
[1] error(s::String)
@ Base ./error.jl:35
[2] VonMisesFisher{Float64}(μ::Vector{Float64}, κ::Float64; checknorm::Bool)
@ Distributions ~/.julia/packages/Distributions/uuqsE/src/multivariate/vonmisesfisher.jl:24
[3] VonMisesFisher
@ ~/.julia/packages/Distributions/uuqsE/src/multivariate/vonmisesfisher.jl:20 [inlined]
[4] VonMisesFisher
@ ~/.julia/packages/Distributions/uuqsE/src/multivariate/vonmisesfisher.jl:31 [inlined]
[5] VonMisesFisher(μ::Vector{Float64}, κ::Int64)
@ Distributions ~/.julia/packages/Distributions/uuqsE/src/multivariate/vonmisesfisher.jl:34
[6] top-level scope
@ REPL[38]:1
```