BUG: Fixed C code printing for Piecewise functions.

C code generation for Piecewise functions was not working for functions
with multiple conditionals. This patch fixes the unbalanced ending parentheses.
I believe that the right paren should be in the format string, perhaps like this: "(%s) ? (\n%s\n)". To mimic what you have now, it should have a leading space if you really want a space before it on the new line.