- Use Popen facilities to constrain the time and memory consumption of a tool.

- Print time and memory consumption of a tool (when verbose is set to true).

N.B. It turns out that the generated PBESs are not OK. Below an example for length=150.

pbes
   mu X1 ( u , w , w , u , w , u , w , v , w , w , u , w , u , w , u , v , v , u , v , u , v , v , w : Int ) = val ( u < 41 ) && val ( w < 74 ) && val ( v < 26 ) && true && ( !X5 => ! false ) ;
   nu X2 = true && ( false ) ;
   mu X3 = true && ( true ) ;
   mu X4 = true && ( true ) ;
   mu X5 = true && ( false ) ;

init X4 ;

It also looks like the generation time is exponential in the length. Clearly this is not acceptable.