more enhancements.
rename cstring_copy to cstring_set.

We need the _copy() name for functions which copy the contents
of an adt, as in a = b;
add cstring_copy
remove cruft
Use cstring more.
uninline functions.
bugfix
Add the status_t

The status_t type is used by functions to return either
success or failure. We use status_t to avoid accidently mixing
status information with integer/bool stuff.
Check for and warn for unused results.
More use of status_t.

We like it. +1.