NewPolka (`pk.h'): convex polyhedra and linear equalities abstract domains

The NEWPOLKA convex polyhedra and linear equalities library is aimed to be used through the APRON interface. However some specific points should be precised. First, NEWPOLKA can use several underlying representations for numbers, which lead to several library variants. Second, some specific functions are needed, typically to allocate managers, and to specify special options.

Use of NewPolka
Allocating NewPolka managers and setting specific options
NewPolka standard options