Changes to Libfiber between r0 and r1

'''Simple Fiber Library'''

Implementation of [fibers] (for [cooperative threading])

http://evanjones.ca/software/threading.html [http://www.rkeene.org/projects/info/resources/threads/libfiber/threading.html]

Mirror of source: http://www.rkeene.org/projects/info/resources/threads/libfiber/libfiber.tar.gz
----
Sample application using Libfiber: http://www.rkeene.org/projects/info/resources/threads/test1-lf.c

Compile:
   * $ cc -o test1-lf test1-lf.c libfiber-sjlj.c; or -->    * $ cc -o test1-lf test1-lf.c libfiber-sjlj.c''; or''
    * $ cc -o test1-lf test1-lf.c libfiber-uc.c; or -->    * $ cc -o test1-lf test1-lf.c libfiber-uc.c''; or''
    * $ cc -o test1-lf test1-lf.c libfiber-clone.c

Legend

     Only in r0
     Only in r1
     -->      Modified slightly between r0 and r1