python: add bindings for ltsmin

* python/spot/ltsmin.i: New file.
* python/Makefile.am: Add it.
* python/spot/impl.i: Add bindings for kripke and fair_kripke.
* tests/python/ltsmin.ipynb: New file.
* tests/Makefile.am, doc/org/tut.org: Add it.
* tests/python/ipnbdoctest.py: Make it possible for notebook
to exit(77).
* debian/control: Make the Python package dependent
on libspotltsmin0.
* python/spot/__init__.py: Typo.

tests/python/ipnbdoctest.py

@@ -185,6 +185,10 @@ def run_cell(kc, cell):
             out.ename = content['ename']
             out.evalue = content['evalue']
             out.traceback = content['traceback']
+
+            # sys.exit(77) is used to Skip the test.
+            if out.ename == 'SystemExit' and out.evalue == '77':
+                sys.exit(77)
         else:
             print("unhandled iopub msg:", msg_type)