Added some assertions about null icons.

client/texture/FlipableIcon.java

@@ -10,6 +10,10 @@ public class FlipableIcon implements IIcon
 	boolean flip_v;
 
 	public FlipableIcon(IIcon o) {
+		
+		if ( o == null )
+			throw new RuntimeException("Cannot create a wrapper icon with a null icon.");
+		
 		original = o;
 		flip_u = false;
 		flip_v = false;

client/texture/FullIcon.java

@@ -10,6 +10,10 @@ public class FullIcon implements IIcon
 	private IIcon p;
 
 	public FullIcon(IIcon o) {
+		
+		if ( o == null )
+			throw new RuntimeException("Cannot create a wrapper icon with a null icon.");
+		
 		p = o;
 	}
 

client/texture/OffsetIcon.java

@@ -13,6 +13,10 @@ public class OffsetIcon implements IIcon
 	private IIcon p;
 
 	public OffsetIcon(IIcon o, float x, float y) {
+		
+		if ( o == null )
+			throw new RuntimeException("Cannot create a wrapper icon with a null icon.");
+		
 		p = o;
 		offsetX = x;
 		offsetY = y;

client/texture/TaughtIcon.java

@@ -12,6 +12,10 @@ public class TaughtIcon implements IIcon
 	private IIcon p;
 
 	public TaughtIcon(IIcon o, float tightness) {
+		
+		if ( o == null )
+			throw new RuntimeException("Cannot create a wrapper icon with a null icon.");
+		
 		p = o;
 		this.tightness = tightness * 0.4f;
 	}