fix trace statements
remove unneeded file
Hash table fixes. More consistently apply mate score correction and
move util functions for this to Hash class.

Update age when accessing an entry from a different age.

Also sample time more often on very fast searches.
optimize Board::between and Board::clear by using pre-computed arrays.
fix data error in betweenSquares
make 7th rank masks const
Update version to 16.2
Revert hashtable changes and other fixes. Keep optimized clear
and between functions.