Optionally depend on HTTP.jl ?

[oxinabox]

The code to solve #21 in #22 is a bit of a hack.
It's using console calls.
It should work on any system, but it is not a nice way to do it.
I'm pretty sure unusual webserver configurations can break it.
See the /tests/examples_flaky.jl.

It might be nice to build and test a solution on top of HTTP.jl.
If it proves more robust, then lazily depend on it.
So that if an user does run into trouble they can either start the REPL with julia -e "using HTTP" -i
or run the script eg julia -e "using HTTP" runtests.jl

[oxinabox]

I am now thinking I might want to hard depend on HTTP.jl,
because the console calls are not working right on Mac and chasing that down is going to be a pain.
just so much flakyness.

But I need either JuliaWeb/HTTP.jl#162
or JuliaWeb/HTTP.jl#160
first and a new tagged release of HTTP.jl

[oxinabox]

closed in #26 by hard depending