* ada_user/Makefile.am, ada_user/ada_user.texi, user/Makefile.am,
user/c_user.texi, user/concepts.t, user/overview.t,
user/preface.texi, user/schedule.t, user/sem.t: Add table of figures.
Add text and graphic of tree illustrating valid combinations of
semaphore attributes.
* user/semaphore_attributes.eps, user/semaphore_attributes.png:
New files.
