A couple of bug fixes

More still need to be done but I'm separating the commits so I don't get overwhelmed lol

- Fixes a bug with the Up-Grade NPC in Saffron. He now properly shows up only after defeating Giovanni.

- Fixes a bug where Silph could be entered before receiving the Poke Flute.

- Silph Gauntlet 5F has a complete remodel, more closely matching the original map found in the leaks.

- One of the Fuchsia Gym Trainers no longer uses a repeat Arbok.

- Wiglett and Wugtrio could learn Rock Slide via TM, which has now been fixed.

- Jacky uses a Porygon in place of Machop, as it ties into his polygonal, Virtua Fighter-inspired sprite.

- Chief uses a Gengar instead of Porygon2 to represent the Silph Scope.

- Omega's and Giovanni 2's levels have been toned down slightly.

- Lance now uses Crocky over Aerodactyl.

- Yujirou's non-initial teams have had their levels reduced to be the same level as the previously-fought Gym Leader, rather than the upcoming one.

- Updated README with additional credits.

data/maps/hide_show_data.asm

@@ -300,10 +300,9 @@ SaffronCityHS:
 	db SAFFRON_CITY, $0A, HIDE                ; HS_SAFFRON_CITY_A
 	db SAFFRON_CITY, $0B, HIDE                ; HS_SAFFRON_CITY_B
 	db SAFFRON_CITY, $0C, HIDE                ; HS_SAFFRON_CITY_C
-	db SAFFRON_CITY, $0D, HIDE                ; HS_SAFFRON_CITY_D
-	db SAFFRON_CITY, $0E, SHOW                ; HS_SAFFRON_CITY_E
+	db SAFFRON_CITY, $0D, SHOW                ; HS_SAFFRON_CITY_D
+	db SAFFRON_CITY, $0E, HIDE                ; HS_SAFFRON_CITY_E
 	db SAFFRON_CITY, $0F, HIDE                ; HS_SAFFRON_CITY_F
-	db SAFFRON_CITY, $1A, HIDE                ; HS_SAFFRON_CITY_UP_GRADE
 Route1HS:
 	db ROUTE_1, $03, HIDE                     ; HS_ROUTE_1_OAK
 Route2HS: