Reduces the indirection in fcgi.c, starts to make the struct template opaque, simplifies the template usage. All with a net negative :-) reads fine to stsp@ (thanks!)

this code is now part of Game of Trees too!

if some of the tp_* function fails, the inner code could free the template too (that's what galileo does), so `tp->tp_ret' would access free'd memory! Instead, add a local variable `tp_ret' to keep track of the return code. While here, drop the `render' shortand that adds the argument call, the template_reset function and adapt the regress.