Pawns namespace refactor

Renaming Entry and Table definitions to make search easier part 1
Material namespace refactor

Make Entry and Table more searchable part 2
Simplify move_to_san()

Nicely simplify disambiguation code.

No functional change.
Retire TTCluster and simplify TT

Also some renaming while there.

No functional change.
Microptimize first_entry() for 32bits

Do a 32bit bitwise 'and' instead of a 64bit
subtract and bitwise 'and'.

This is possible because even in the biggest
hash table case (8GB) the number of entries
is 2^29 so storable in an unsigned int.

No functional change.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	src/tt.cpp