TAF-Kit stands for Typed Automata Function Kit, that is to say,
programs that deal with fixed type automata, on the command line.

- src/taf-kit: New. TAF-Kit directory.

- src/taf-kit/b_commands.cc: New. Add commands specific to Boolean
automata.

The following files will be common to all TAF-Kit binaries:

- src/taf-kit/commands.hh: New.
- src/taf-kit/edit_automaton.hh,
- src/taf-kit/edit_automaton.hxx: New. `edit_automaton' and 
`create_automaton' functions.
- src/taf-kit/commands_macros.hh: New. Useful macros to define commands.
- src/taf-kit/getters.hh,
- src/taf-kit/getters.hxx: New. Getters for expressions, automata, ...
- src/taf-kit/common.hh: New.
- src/taf-kit/predefined_alphabets.hh: New.
- src/taf-kit/common_commands.hh: New.
- src/taf-kit/main.cc: New.

- src/taf-kit/Makefile.am: New.
- src/Makefile.am: Include TAF-Kit as a subdirectory if its build has
been requested.
- config/vcsn_taf_kit.m4: New. Check for Curses and enable the build
of TAF-Kit on demand.
- configure.ac: Update accordingly.