hoa: output "unambiguous" only for non-deterministic automata by default

* src/twaalgos/hoa.cc: Output do not output "unambiguous" if the
automaton is deterministic.  Add option "v" to cancel this restriction,
and also output "no-univ-branch".
* src/twaalgos/hoa.hh: Document the "v" option.
* src/tests/readsave.test: Test it.
* src/tests/unambig.test: Adjust for unambiguous not being output
if the automaton is deterministic.
* src/bin/common_aoutput.cc, NEWS: Document it.
* doc/org/hoa.org: Add a summary table about how properties are handled.
* src/twa/twa.hh (prop_deterministic): Setting this should also
set the unambiguous property.
* src/twaalgos/isunamb.cc: Simplify the property check.

src/tests/readsave.test

@@ -741,3 +741,25 @@ EOF
 diff output4 expect4
 diff output4b expect4
 diff output4c expect4
+
+$autfilt -Hv --small input4 >output5
+
+cat >expect5<<EOF
+HOA: v1
+States: 3
+Start: 1
+AP: 2 "a" "b"
+acc-name: Buchi
+Acceptance: 1 Inf(0)
+properties: no-univ-branch trans-labels explicit-labels state-acc
+properties: deterministic unambiguous inherently-weak
+--BODY--
+State: 0
+[1] 2
+State: 1
+[0] 0
+State: 2 {0}
+[0] 2
+--END--
+EOF
+diff output5 expect5