ast modifs and additional arrow_taint phase to retrieve which arrow "protects" / "taints" which variable

- Bugs in partial evaluation for equalities among bool constants
  and a nice recursive call generating a stack overflow! Now solved
- Setup a timeout for z3 in seal
- Better log for seal

- real constants are hidden in Real.ml{i} module

- copy_var_decl now keeps the generated type

Contract resolution still need to be done as well as dealing with the machine code level and so on.

- Modules now is more integrated and performed the building of the type/clock env.
  previously some computation were performed twice by different functions. Some of these functions have been moved from compiler_common to modules

- Contract were extended with list of statements.

Adapted the parser/types/constructors for cocospec syntax

- Renamed type declarations as lustre_types and machine_code_types

- program type renamed as program_t
- Initiating the lustrev tool with dependencies to z3 and seal.

[general] large modification: added machine types, a second typing phase dealing with machine types (eg uint8)
          typing was transformed as a functor and parametrized by basic types (int/real/bool)
          it can also be applied multiple times on the same program

- EMF backend now impose the optimization level to be set to 0 in order to avoid equation elimination that would render traceability difficult
- Options.ml has been split into Options.ml / Options_management.ml. Options.ml only contains references and no functions

- Addtional encapsulation of machine_code instr in a struct to enable future extension of type with more metadata.
- Improved EMF backend with META information

- no more classic display for ocamlc
- compilation warnings removed

- bug in expansion of array accesses with constant arrays
- bug in printing complex array indexes (not C compliant)
- bug wrt C99 typing policy for constant arrays
- bug in signaling wrong useless static input