generates ASCII definition of a Scilab function
txt = tree2code(tree, prettyprint)
a macro tree (coming from macr2tree).
an optional boolean value:
generated code is indented and beautified
generated code is not beautified (default)
a column vector of strings, the text giving the Scilab instructions.
Given a loaded Scilab function "tree" (returned by macr2tree), tree2code allows to
re-generate the code.