Retire #ifdef SYZYGY macro

It just clutters the code for no
real reason.

No functional change.

Resolves #139
Rewrite TBScore in uci_pv()

Streamline the code and make
it understandable.

No functional change.

Resolves #135
Cleaning Syzygy profiling data

Updating the makefile so that the clean and gcc-profile-clean targets also
remove the profiling data files in the syzygy directory.

No functional change.

Resolves #136
Remove CONNECTED_KINGS from Syzygy code

No functional change

Resolves #140
Retire total_piece_count()

We really don't need to uglify in this way
our nice count() API with this ad-hoc hack.

So remove the hack and use the already
existing infrastructure.

No functional change.

Resolves #134