Fix format method on JVM and JS

core/src/main/js/org/isoron/platform/io/JsStrings.kt

@@ -19,6 +19,14 @@
 
 package org.isoron.platform.io
 
-actual fun sprintf(format: String, vararg args: Any?): String {
-    return js("vsprintf")(format, args)
+actual fun format(format: String, arg: String): String {
+    return js("vsprintf")(format, arg) as String
+}
+
+actual fun format(format: String, arg: Int): String {
+    return js("vsprintf")(format, arg) as String
+}
+
+actual fun format(format: String, arg: Double): String {
+    return js("vsprintf")(format, arg) as String
 }

core/src/main/jvm/org/isoron/platform/io/Strings.kt

@@ -19,6 +19,11 @@
 
 package org.isoron.platform.io
 
-actual fun sprintf(format: String, vararg args: Any?): String {
-    return String.format(format, *args)
-}
+actual fun format(format: String, arg: String): String =
+        String.format(format, arg)
+
+actual fun format(format: String, arg: Int): String =
+        String.format(format, arg)
+
+actual fun format(format: String, arg: Double): String =
+        String.format(format, arg)