- Change memory allocation to thread a context structure through
the code rather than using globals (which would require a
-lpthread and some locking to become threadsafe).
- Remove a few configuration options (the "private memory" space,
and K&R style headers).
- Prefix exported symbols with jvp_ to prevent libc conflicts.
- Add jvp_dtoa.h
- Include netlib's g_fmt.c into dtoa.c
- Add a few not-strictly-necessary initialisations in order to
compile cleanly with gcc -Wall
