Implement push!

[bryaan]

Can we add something like this?

function Base.push!(data::Lockable{Vector{T},ReentrantLock}, elements) where {T}
    lock(data) do vec
        push!(vec, elements)
    end
end

[quinnj]

I don't think it's really necessary. While not strict type piracy, this is generally considered "type light robbbery" in that we (the ConcurrentUtilities.jl) package don't own the Vector type, so we shouldn't be overloading for it.

But the bigger reason is that it's so little code, it just doesn't seem worth it to "hide" the fact that your Lockable{Vector} is actually a Lockable instead of a Vector.