Add an UTF-8 option to the web interface.

* wrap/python/ajax/ltl2tgba.html: Add the checkbox.
* wrap/python/ajax/css/ltl2tgba.css: Add the necessary class.
* wrap/python/ajax/protocol.txt: Add the new option.
* wrap/python/ajax/spot.in: Handle it.
* wrap/python/ajax/README: Add a few lines to explain
how to run the CGI script from the command line for debugging.

wrap/python/ajax/protocol.txt

@@ -74,3 +74,7 @@ Automaton simplifications (pick many)
   as=ps   Prune SCC
   as=wd   WDBA minimiztion
   as=ds   Direct Simulation reduction
+
+Global options
+
+  g=8     Enable UTF-8 output.