GUI:
- added an option to see ROM info to menu;
- started connecting zapper to GUI;

APU:
- fixed returning results on reading from write-only registers;

CPU:
- fixed timing on OAM and DMC DMA.

PPU:
- fixed pixels not rendering in specific cases

Board:
- fixed returning results on reading from the address range $4020-$5FFF;
- added mapper 24 (VRC6a);
- added mapper 26 (VRC6b);
- added mapper 67 (Sunsoft-3);
- added mapper 68 (Sunsoft-4);
- added mapper 69 (Sunsoft FME-7);
- added mapper 70 (BANDAI-74*161/161/32);
- added mapper 118 (TxSROM);
- added mapper 119 (TQROM);
- added mapper 152 (TAITO-74*161/161/32);
- added mapper 255 (110/115-in-1).