acc: parse standard acceptance names

* src/twa/acc.cc, src/twa/acc.hh: Add method to create
standard acceptance conditions, and adjust the parse_acc_code
to recognize them
* wrap/python/spot_impl.i (acc_cond::acc_code): Add a printer.
* wrap/python/tests/accparse.ipynb: New test file.
* wrap/python/tests/Makefile.am: Add it.
* src/tests/satmin2.test: Use the new syntax.

wrap/python/spot_impl.i

@@ -344,6 +344,22 @@ spot::ltl::formula_ptr_less_than>;
   std::string __str__() { return spot::ltl::to_string(self); }
 }
 
+%extend spot::acc_cond::acc_code {
+  std::string __repr__()
+  {
+    std::ostringstream os;
+    os << *self;
+    return os.str();
+  }
+
+  std::string __str__()
+  {
+    std::ostringstream os;
+    os << *self;
+    return os.str();
+  }
+}
+
 %nodefaultctor std::ostream;
 namespace std {
   class ostream {};