Test cases for exhaust mode

Signed-off-by: Pauli Nieminen <suokkos@gmail.com>
Port exhaust mode to bit board

Exhaust mode is super fast way to generate two remaining hands when two
other are completely known. Porting it to the new bit board world and
removing ifdef guards makes it very useful option when trying to do
single dummy analyze.

Signed-off-by: Pauli Nieminen <suokkos@gmail.com>