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
Refactor syzygy code in search

Move to SF coding style.

Also skip calculating piece count in search()
when TB are not found (!TBCardinality)

No functional change.
Move TB stuff under Tablebases namespace

Simplified also some logic while there.

TBLargest needs renaming too, but itis for
a future patch because touches also syzygy
directory stuff.

No functional change.
Explicitly pass RootMoves to TB probes

Currently Search::RootMoves is accessed and even
modified by TB probing functions in a hidden
and sneaky way.

This is bad practice and makes the code tricky.
Instead explicily pass the vector as function
argument so to clarify that the vector is modified
inside the functions.

No functional change.