Python bindings for leeloo::port and leeloo::port_list_intervals

Moreover, delete the u64 bindings, as they need 128-bit capabilities to
work in all cases.
Fixes and helpers for port/port_list_intervals
Cleaner interface for list_intervals_random (size* functions)
integer_cast: check for overflows, and futur support for VLI
VLI tests (support incoming)
Fix misues of size_type vs. base_type

The wrong type was use to compute for instance the size of the object
(that is the number of integers representated). The size_type defines
only the type for the number of *intervals*.
Distribution of new header files