- loading lusi
- loading lib in lusi files: "in m" is now "lib m"

Changed the load of lusi files: imported nodes or function can specify the linking lib and/or use a classical C prototype (without pointers).
Parse updated as well as Makefile generation.

changed name generation to avoid conflict with C predefined symbols; added checking for declared but not defined node symbol

 - debugged liveness analysis...

 - added computation of a reuse policy (depending on types)
 - not yet used though, would have to change code generation
   in order to be useful...

 The 'function' keyword is for stateless nodes only,
 the 'node' keyword is any kind of node.
 Improves compilation and paves the way for more optimizations.

   (to turn conditionals into merges, which yield more efficient C code)

corrected bugs in clock generalization that produced pessimistic C code (not wrong though); corrected bug with node importation policy wrt (re)declaration, (re)definition...

 - added constant definition with a struct type
 - added checking for multiple definitions of nodes (behavior was buggy)
 - better and more uniform error messages
   for undefined/already defined symbols

 We still need struct expressions...

Cette ligne, et les suivantes ci-dessous, seront ignorées--

M    trunk/src/corelang.mli
M    trunk/src/type_predef.ml
M    trunk/src/main_lustre_compiler.ml
M    trunk/src/types.ml
M    trunk/src/printers.ml
M    trunk/src/typing.ml
M    trunk/src/horn_backend.ml
M    trunk/src/parser_lustre.mly
M    trunk/src/env.ml
M    trunk/src/c_backend.ml
M    trunk/src/corelang.ml

corrected bug in arrow macros names, added storage attribute for static alloc macros, option -d now creates the destination directory if needed, with current dir as file permissions

 - arrows are now factorized out and become part of include
   as files arrow.h and arrow.c
 - no more arrows in generated code
 - compiling and linking arrow.c is only necessary
   in case of dynamic allocation 
 - version now includes installation prefix (for the standard lib)
   and svn number

- added clock checking between interface and implementation files