hoa: swallow the neverclaim parser

This way we can easily parse a stream of HOAs intermixed with
neverclaims.

* src/hoaparse/hoaparse.yy, src/hoaparse/hoascan.ll: Add rules
for neverclaims, adjusted from src/neverparse/neverclaimparse.yy
and src/neverparse/neverclaimparse.ll.
* src/hoaparse/public.hh, NEWS: Update documentation.
* src/neverparse/: Remove this directory.
* README, configure.ac, src/Makefile.am: Adjust accordingly.
* src/tgbatest/ltl2tgba.cc, src/bin/ltlcross.cc: Use HOA
parser to read neverclaims.
* src/tgbatest/hoaparse.test, src/tgbatest/neverclaimread.test: Adjust.

src/Makefile.am

@@ -25,10 +25,10 @@ AUTOMAKE_OPTIONS = subdir-objects
 # List directories in the order they must be built.  Keep tests at the
 # end, after building '.' (since the current directory contains
 # libspot.la needed by the tests)
-SUBDIRS = misc priv ltlenv ltlast ltlvisit ltlparse graph tgba		\
-          tgbaalgos tgbaparse ta taalgos kripke neverparse		\
-          kripkeparse dstarparse hoaparse . bin ltltest graphtest	\
-          tgbatest kripketest sanity
+SUBDIRS = misc priv ltlenv ltlast ltlvisit ltlparse graph tgba	\
+          tgbaalgos tgbaparse ta taalgos kripke kripkeparse	\
+          dstarparse hoaparse . bin ltltest graphtest tgbatest	\
+          kripketest sanity
 
 lib_LTLIBRARIES = libspot.la
 libspot_la_SOURCES =
@@ -43,7 +43,6 @@ libspot_la_LIBADD =  \
   ltlparse/libltlparse.la \
   ltlvisit/libltlvisit.la \
   misc/libmisc.la \
-  neverparse/libneverparse.la \
   priv/libpriv.la \
   taalgos/libtaalgos.la \
   ta/libta.la \