Update doom with new tiles, add panel tile type

Fix nothing tile loading #475

graphics/wall/panel/LICENSE.txt

@@ -0,0 +1,6 @@
+Derived from
+
+190+ Pixel Art Assets (Sci-fi & Forest)
+by Gabsond
+https://opengameart.org/content/190-pixel-art-assets-sci-fi-forest
+http://creativecommons.org/publicdomain/zero/1.0/

missions/doom.cdogscpn/campaign.json

@@ -1,5 +1,5 @@
 {
-	"Version": 13,
+	"Version": 15,
 	"Title": "Doom",
 	"Author": "Cong",
 	"Description": "Stuck on Mars for insubordination, you are a marine who has just arrived at the dullest assignment in the system. They say your employer, UAC, are performing secret experiments to do with teleportation, but what could go wrong with that?",

missions/doom.cdogscpn/characters.json

@@ -1,12 +1,12 @@
 {
-	"Version": 12,
+	"Version": 13,
 	"Characters": [{
-		"Class": "Cyber Jones",
-		"Skin": "b79536",
-		"Arms": "646464",
-		"Body": "646464",
-		"Legs": "646464",
-		"Hair": "646464",
+		"Class": "Cyborg",
+		"Skin": "b79536ff",
+		"Arms": "646464ff",
+		"Body": "646464ff",
+		"Legs": "646464ff",
+		"Hair": "000000ff",
 		"speed": 128,
 		"Gun": "Marine Shotgun",
 		"maxHealth": 20,
@@ -17,12 +17,12 @@
 		"actionDelay": 20
 	},
 	{
-		"Class": "Cyber Smith",
-		"Skin": "b79536",
-		"Arms": "b79536",
-		"Body": "ff8136",
-		"Legs": "882800",
-		"Hair": "149c14",
+		"Class": "Cyborg",
+		"Skin": "b79536ff",
+		"Arms": "b79536ff",
+		"Body": "ff8136ff",
+		"Legs": "882800ff",
+		"Hair": "000000ff",
 		"speed": 192,
 		"Gun": "Marine Pistol",
 		"maxHealth": 30,
@@ -34,11 +34,11 @@
 	},
 	{
 		"Class": "Ogre",
-		"Skin": "882800",
-		"Arms": "d25106",
-		"Body": "d25106",
-		"Legs": "d25106",
-		"Hair": "c00000",
+		"Skin": "882800ff",
+		"Arms": "d25106ff",
+		"Body": "d25106ff",
+		"Legs": "d25106ff",
+		"Hair": "c00000ff",
 		"speed": 192,
 		"Gun": "Imp Fireball",
 		"maxHealth": 40,
@@ -49,12 +49,12 @@
 		"actionDelay": 15
 	},
 	{
-		"Class": "Evil Ogre",
-		"Skin": "ff76f5",
-		"Arms": "ff76f5",
-		"Body": "ff76f5",
-		"Legs": "ff76f5",
-		"Hair": "fffffe",
+		"Class": "Ogre",
+		"Skin": "ff76f5ff",
+		"Arms": "ff76f5ff",
+		"Body": "ff76f5ff",
+		"Legs": "ff76f5ff",
+		"Hair": "000000ff",
 		"speed": 320,
 		"Gun": "Monster Bite",
 		"maxHealth": 70,
@@ -65,12 +65,12 @@
 		"actionDelay": 13
 	},
 	{
-		"Class": "Evil Ogre",
-		"Skin": "ff76f5",
-		"Arms": "ff76f5",
-		"Body": "ff76f5",
-		"Legs": "ff76f5",
-		"Hair": "fffffc",
+		"Class": "Ogre",
+		"Skin": "ff76f5ff",
+		"Arms": "ff76f5ff",
+		"Body": "ff76f5ff",
+		"Legs": "ff76f5ff",
+		"Hair": "000000ff",
 		"speed": 320,
 		"Gun": "Monster Bite",
 		"maxHealth": 70,
@@ -81,12 +81,12 @@
 		"actionDelay": 13
 	},
 	{
-		"Class": "Evil Ogre",
-		"Skin": "ff76f5",
-		"Arms": "9c5858",
-		"Body": "ff76f5",
-		"Legs": "ff8136",
-		"Hair": "5b5b5b",
+		"Class": "Ogre",
+		"Skin": "ff76f5ff",
+		"Arms": "9c5858ff",
+		"Body": "ff76f5ff",
+		"Legs": "ff8136ff",
+		"Hair": "000000ff",
 		"speed": 256,
 		"Gun": "Baron Fireball",
 		"maxHealth": 500,

src/cdogs/tile_class.c

@@ -207,7 +207,7 @@ void TileClassInitDefault(
 }
 void TileClassReloadPic(TileClass *t, PicManager *pm)
 {
-	if (t->Name != NULL)
+	if (t->Name != NULL && strlen(t->Name) != 0)
 	{
 		// Generate the pic in case it doesn't exist
 		PicManagerGenerateMaskedStylePic(