Added OptionalString#asBoolean

Author: LatvianModder

src/main/java/dev/latvian/apps/tinyserver/OptionalString.java

@@ -57,6 +57,18 @@ public <T> T as(Function<String, T> mapper) {
 		return as(mapper, null);
 	}
 
+	public boolean asBoolean() {
+		return asBoolean(false);
+	}
+
+	public boolean asBoolean(boolean def) {
+		if (value == null) {
+			return def;
+		}
+
+		return value.equalsIgnoreCase("true") || value.equalsIgnoreCase("yes") || value.equalsIgnoreCase("on") || value.equalsIgnoreCase("1");
+	}
+
 	public int asInt() {
 		return asInt(0);
 	}