add deprecation

Author: stevengj

README.md

@@ -64,7 +64,7 @@ s = SobolSeq(N)
 ```
 Then
 ```
-x = next(s)
+x = next!(s)
 ```
 returns the next point (a `Vector{Float64}`) in the sequence; each point
 lies in the hypercube [0,1]<sup>N</sup>.   You can also compute the next
@@ -111,7 +111,7 @@ the [0,1]×[0,1] unit square!
 using Sobol
 using PyPlot
 s = SobolSeq(2)
-p = hcat([next(s) for i = 1:1024]...)'
+p = hcat([next!(s) for i = 1:1024]...)'
 subplot(111, aspect="equal")
 plot(p[:,1], p[:,2], "r.")
 ```

src/Sobol.jl

@@ -78,6 +78,9 @@ function next!(s::SobolSeq, x::AbstractVector{<:AbstractFloat})
 end
 next!(s::SobolSeq) = next!(s, Array{Float64,1}(undef, ndims(s)))
 
+import Base: next
+@deprecate next(s::AbstractSobolSeq) next!(s)
+
 # if we know in advance how many points (n) we want to compute, then
 # adopt the suggestion of the Joe and Kuo paper, which in turn
 # is taken from Acworth et al (1998), of skipping a number of