Remove support for state-based alternating automata.

This was never actually used and we have a new implementation of
alternating automata coming.

* src/saba/, src/sabaalgos/, src/sabatest/: Remove.
* src/Makefile.am, configure.ac, README: Adjust.
* NEWS: Mention it.

configure.ac

@@ -193,10 +193,6 @@ AC_CONFIG_FILES([
   src/neverparse/Makefile
   src/priv/Makefile
   src/sanity/Makefile
-  src/saba/Makefile
-  src/sabaalgos/Makefile
-  src/sabatest/defs
-  src/sabatest/Makefile
   src/tgbaalgos/gtec/Makefile
   src/tgbaalgos/Makefile
   src/tgba/Makefile