various updates here and there, lots of stuff done, but nothing
exceptional

Mostly I just worked on updating library functions to use signals and to
use the new signature for functions with rest args.

Notable is that I updated format.c, I changed the global
current_environment to current_env cause I could'nt stand typing that
every time, I changed the sexp field simple_string to c_string and
changed / added macros for siginaling simple errors with string values.