Add Kotlin Unit tests

src/test/kotlin/org/hmcore/tests/KotlinTests.kt

@@ -0,0 +1,17 @@
+package org.hmcore.tests
+
+import org.hmcore.HMCore
+import org.junit.jupiter.api.Test
+
+// The primary function of the Kotlin tests is to ensure Kotlin-specific features are preserved
+// Meaning some tests might only make sure features work at compile time.
+
+@Test
+fun `Module should support index access operator`() {
+    HMCore.modules["ores"]!!["other"]
+}
+
+@Test
+fun `Module should support 'in' keyword`() {
+    HMCore.modules["ores"]?.let { "copper" in it }
+}