dictionaries (map of BDD variables to LTL formulae).  This was
cumbersome, because to multiply two automata we had to build a
common dictionary (the union of the two LTL formula spaces), and
install wrappers to translate each automaton's BDD answers into
the common dictionary.  This translation, that had to be repeated
when several products were nested, was time consuming and was a
hindrance for some optimizations.
In the new scheme, all automata involved in a product must
share the same dictionary.  An empty dictionary should be
constructed by the user and passed to the automaton' constructors
as necessary.
This huge change removes most code than it adds.

* src/Makefile.am (libspot_la_LIBADD): Add misc/libmisc.la.
* src/misc/bddalloc.hh, src/misc/bddalloc.cc: New files.  These
partly replace src/tgba/bddfactory.hh and src/tgba/bddfactory.cc.
* src/misc/Makefile.am: Adjust to build bddalloc.hh and bddalloc.cc.
* src/tgba/bddfactory.hh, src/tgba/bd...