busybox

Ok, this is a pretty major update to sh.c.  I renamed all the variables and
function names to conform with the style guide.  I also did a lot of work on
the if-then-alse-fi logic and added prototype (i.e. it segfaults when enabled)
line continuation support.

Furthermore, this patch includes Larry Doolittle's work on restructuring some
of the data structures that represent the job and child_program, allowing
several simplifications and fixing several bugs.

 -Erik