tutorial update

[felixrehren]

The tutorial is a bit out of date:

• running Julia 0.4.7
• "Plotting in Julia" raises "WARNING: [a] concatenation is deprecated; use collect(a) instead"
• "Multiple Dispatch" raises "WARNING: Base.String is deprecated, use AbstractString instead."
• "Calling C" raises "WARNING: Base.Uint8 is deprecated, use UInt8 instead." and "WARNING: deprecated syntax "[a=>b, ...]" at In[35]:7."
• I see no widgets in "Interactive Widgets"

I'm going to have a look at making the necessary updates. Comments welcome.

[felixrehren]

An issue in Julia 0.5 (WARNING: Base.writemime is deprecated.) in "Calling C" seems to be fixed by getting a new checkout of PyPlot, cf. https://github.com/JuliaLang/IJulia.jl/issues/426. I don't know how to do this, can someone advise ?

Finally, the fonts for making xkcd-style graphs are missing.