use compact mode when printing by default

[Roger-luo]

currently, when executing the Literate script, it redirects the IO to a buffer

https://github.com/fredrikekre/Literate.jl/blob/master/src/Literate.jl#L495

this is not very consistent with what people will see in a REPL and could be inconvenient
if it is built with web pages. It would be nice to have an IOContext that has :compact=>true
as default, or at least have an option for this

[fredrikekre]

See #127, tkf/DisplayAs.jl#14.

[Roger-luo]

ah thanks!

[Roger-luo]

@fredrikekre I think DisplayAs doesn't really solve this problem, one need to use that explicit which is not this issues describes - shouldn't the default text/plain output be consistent with REPL? this currently frequently blow up the outputs for me when there is a large array, while everything works just fine in REPL. I think at least the printing should use :compact=>true by default which respects the printing protocols