Consider translating top-level echo as print/println

[dundalek]

Printing with echo:

echo -n foo
echo bar

Gets translated as (which works correctly):

(shell "echo" "-n" "foo")
(shell "echo" "bar")

We could make the output for top-level echos (that are not part of a pipeline) a bit nicer and idiomatic if we translate them as:

(print "foo")
(println "bar")

[pesterhazy]

Hm, of course as you pointed out, the naive implementation doesn't work in pipe or command substitution contexts.

I'd like println to work in those contexts as well, but that'll require a bit more refactoring