new pos/bb funcs, legal(), better castling gen, etc. [see commit details]

- new sq_pinners
- new pseudo_is_legal() (unfinished)
- improve castling pseudo move gen

- more position and lower level bitboard helper funcs:
  - pos_{_occ,between_occ,between_count,pinners}
  - bb_{rank,file,rel_rank,_sq_aligned,_sq_between)
- rename some bitboard globals
- replace bb ranks/files enums with defines (issue with clang)
  -> Need to find a way to use enum safely
- tests:
  - add common-test.h
  - new attack-test.c

src/hyperbola-quintessence.c

@@ -132,17 +132,17 @@ static bitboard_t hyperbola_moves(const bitboard_t pieces, const square_t sq,
 
 static bitboard_t hyperbola_file_moves(bitboard_t occ, square_t sq)
 {
-    return hyperbola_moves(occ, sq, bb_file[sq]);
+    return hyperbola_moves(occ, sq, bb_sqfile[sq]);
 }
 
 static bitboard_t hyperbola_diag_moves(bitboard_t occ, square_t sq)
 {
-    return hyperbola_moves(occ, sq, bb_diag[sq]);
+    return hyperbola_moves(occ, sq, bb_sqdiag[sq]);
 }
 
 static bitboard_t hyperbola_anti_moves(bitboard_t occ, square_t sq)
 {
-    return hyperbola_moves(occ, sq, bb_anti[sq]);
+    return hyperbola_moves(occ, sq, bb_sqanti[sq]);
 }
 
 bitboard_t hyperbola_bishop_moves(bitboard_t occ, square_t sq)