output of eig() is formatted in a non-obvious way

[StefanKarpinski]

@HomerReid wrote:

output of eig() is formatted in a non-obvious way

 julia> eig([1.0 2.0; 2.0 1.0])
 (-1.0 0.0 
 0.0 3.0 ,-0.70710678118654746 0.70710678118654746 
 0.70710678118654746 0.70710678118654746 )

This is related to #25 and #29, but should be put down specifically because it's something people are likely to notice fast.

[JeffBezanson]

Here's an idea: have an ismultiline(x) predicate that tries to tell you whether printing x is likely to take multiple lines. Then printing aggregates like tuples can insert line breaks before big things.

Maybe we should add a header line to printed arrays like "2x2 Float64 Array". Or at least use that format for printing empty arrays.

[ViralBShah]

We actually need to review our entire printing stuff, keeping the web repl in mind. There are a number of other printing enhancements that are required.

It seems that we may want an intermediate presentation layer, which can be adapted to different UIs.