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

- 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

Impact:
- EMF backend has an extra machines argument
- specific option to avoid merge of ite constructs
- set_backend function to improve backend selection

Most code was extracted from seahorn_backend through c0f8

- allow multiple -I dir, will be used in order (first one declared
  is first used)

- when declaring a global library #open <foo>, foo is first checked
  in local folders, than in global one (install path). This
  does not apply to local libraries opened with #open "foo".

mostly a recovery of an ancient svn repo: mutations