* basic::collec() never worked correctly on non-polynomials till now.

* basic::collec() never worked correctly on non-polynomials till now.
  We simply correct for the missing terms, which makes it at least
  algebraically correct (suggested by Pearu Peterson).
* Added support to print out LaTeX-style, based on some work by Stefan
  Weinzierl:
  - print.h: added a class print_latex().
  - function.pl: added function_options::latex_name() because there was
    no good way of setting that name before.
  - inifncs*.cpp: use it.
  - *.cpp: switch to see if print_context is actually print_latex and
    then change the style.
* Fixed some stupid bugs in sections that were #define'd away for gcc-2.95.