nice bug correction wrt constants with a large number of digits. Would raise exception when comparing these constants

Intregrate all modifs by Teme et al

Solved some issues with commited code (like it doesn't compile). The code was written by Teme's student and
- did not rely on existing typing.ml function
- used strange fprintf code

Code was refactored but old stuff kept in comment just in case. Will have to be cleaned at some point.

Arrays

This is not needed on Linux and it is not supported on Darwin (Mac OS)