add AssetLoadingException

src/main/java/ca/blarg/gdx/assets/AssetLoadingException.java

@@ -0,0 +1,31 @@
+package ca.blarg.gdx.assets;
+
+public class AssetLoadingException extends RuntimeException {
+	String assetFilename;
+	String detailMessage;
+
+	public AssetLoadingException(String assetFilename, String message) {
+		super(message);
+		this.assetFilename = assetFilename;
+		setDetailMessage(assetFilename, message);
+	}
+
+	public AssetLoadingException(String assetFilename, String message, Throwable cause) {
+		super(message, cause);
+		this.assetFilename = assetFilename;
+		setDetailMessage(assetFilename, message);
+	}
+
+	private void setDetailMessage(String assetFilename, String message) {
+		detailMessage = String.format("%s: %s", assetFilename, message);
+	}
+
+	@Override
+	public String getMessage() {
+		return detailMessage;
+	}
+
+	public String getAssetFilename() {
+		return assetFilename;
+	}
+}