Moved callbacks to ZIPR functionality

.gitattributes

callbacks/Makefile.in

callbacks/configure

callbacks/configure.in

callbacks/example/Makefile.in

callbacks/example/callback.c

callbacks/lib/Makefile.in

callbacks/lib/crt.s

callbacks/libc/Makefile.in

callbacks/libc/include/cgc.h

callbacks/libc/include/malloc.h

callbacks/libc/include/stdint.h

callbacks/libc/include/stdlib.h

callbacks/libc/include/syscall.h

callbacks/libc/include/unistd.h

callbacks/libc/src/Makefile.in

callbacks/libc/src/cgc.s

callbacks/libc/src/malloc.c

callbacks/libc/src/unistd.c