Many deprecation warnings on standard use

[lbjarre]

Running the package on Julia 1.1, I get a lot of deprecation warnings:

$ cat qhull-test.jl 

using QHull

points = rand(10, 2)
hull = chull(points)
display(hull)

$ julia qhull-test.jl 
┌ Warning: `getindex(o::PyObject, s::Symbol)` is deprecated in favor of dot overloading (`getproperty`) so elements should now be accessed as e.g. `o.s` instead of `o[:s]`.
│   caller = chull(::Array{Float64,2}) at QHull.jl:34
└ @ QHull ~/.julia/packages/QHull/yeRSS/src/QHull.jl:34
┌ Warning: `getindex(o::PyObject, s::AbstractString)` is deprecated in favor of dot overloading (`getproperty`) so elements should now be accessed as e.g. `o."s"` instead of `o["s"]`.
│   caller = chull(::Array{Float64,2}) at QHull.jl:35
└ @ QHull ~/.julia/packages/QHull/yeRSS/src/QHull.jl:35
┌ Warning: `getindex(o::PyObject, s::AbstractString)` is deprecated in favor of dot overloading (`getproperty`) so elements should now be accessed as e.g. `o."s"` instead of `o["s"]`.
│   caller = chull(::Array{Float64,2}) at QHull.jl:36
└ @ QHull ~/.julia/packages/QHull/yeRSS/src/QHull.jl:36
┌ Warning: `getindex(o::PyObject, s::AbstractString)` is deprecated in favor of dot overloading (`getproperty`) so elements should now be accessed as e.g. `o."s"` instead of `o["s"]`.
│   caller = chull(::Array{Float64,2}) at QHull.jl:38
└ @ QHull ~/.julia/packages/QHull/yeRSS/src/QHull.jl:38
┌ Warning: `getindex(o::PyObject, s::AbstractString)` is deprecated in favor of dot overloading (`getproperty`) so elements should now be accessed as e.g. `o."s"` instead of `o["s"]`.
│   caller = chull(::Array{Float64,2}) at QHull.jl:42
└ @ QHull ~/.julia/packages/QHull/yeRSS/src/QHull.jl:42
┌ Warning: `getindex(o::PyObject, s::AbstractString)` is deprecated in favor of dot overloading (`getproperty`) so elements should now be accessed as e.g. `o."s"` instead of `o["s"]`.
│   caller = chull(::Array{Float64,2}) at QHull.jl:43
└ @ QHull ~/.julia/packages/QHull/yeRSS/src/QHull.jl:43
┌ Warning: `getindex(o::PyObject, s::AbstractString)` is deprecated in favor of dot overloading (`getproperty`) so elements should now be accessed as e.g. `o."s"` instead of `o["s"]`.
│   caller = chull(::Array{Float64,2}) at QHull.jl:44
└ @ QHull ~/.julia/packages/QHull/yeRSS/src/QHull.jl:44
Convex Hull of 10 points in 2 dimensions
Hull segment vertex indices:
[4, 8, 6, 3, 9]
Points on convex hull in original order:

[0.14431 0.70416; 0.874876 0.0934001; 0.561833 0.871743; 0.842075 0.889761; 0.192936 0.0327743]
$ julia --version
julia version 1.1.0

I assume that getindex methods with ::PyObject come from the function calls to the python package.
#19 might therefore fix this indirectly.