Move everything under kotlin-native folder

I was forced to manually do update the following files, because otherwise
they would be ignored according .gitignore settings. Probably they
should be deleted from repo.

Interop/.idea/compiler.xml
Interop/.idea/gradle.xml
Interop/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_runtime_1_0_3.xml
Interop/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_1_0_3.xml
Interop/.idea/modules.xml
Interop/.idea/modules/Indexer/Indexer.iml
Interop/.idea/modules/Runtime/Runtime.iml
Interop/.idea/modules/StubGenerator/StubGenerator.iml
backend.native/backend.native.iml
backend.native/bc.frontend/bc.frontend.iml
backend.native/cli.bc/cli.bc.iml
backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2Native.kt
backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2NativeCompilerArguments.kt
backend.native/tests/link/lib/foo.kt
backend.native/tests/link/lib/foo2.kt
backend.native/tests/teamcity-test.property

kotlin-native/backend.native/tests/objcexport/topLevelMangling.swift

@@ -0,0 +1,26 @@
+import Kt
+
+private func testFunctionsInDifferentFilesAreNotMangled() throws {
+    try assertEquals(actual: TopLevelManglingAKt.foo(), expected: "a1")
+    try assertEquals(actual: TopLevelManglingBKt.foo(), expected: "b1")
+}
+
+private func testPropertiesInDifferentFilesAreNotMangled() throws {
+    try assertEquals(actual: TopLevelManglingAKt.bar, expected: "a2")
+    try assertEquals(actual: TopLevelManglingBKt.bar, expected: "b2")
+}
+
+private func testFunctionsInSameFileAreMangled() throws {
+    try assertEquals(actual: TopLevelManglingAKt.sameNumber(value: Int32(1)), expected: 1)
+    try assertEquals(actual: TopLevelManglingAKt.sameNumber(value_: Int64(2)), expected: 2)
+}
+
+class TopLevelManglingTests : SimpleTestProvider {
+    override init() {
+        super.init()
+
+        test("TestFunctionsInDifferentFilesAreNotMangled", testFunctionsInDifferentFilesAreNotMangled)
+        test("TestPropertiesInDifferentFilesAreNotMangled", testPropertiesInDifferentFilesAreNotMangled)
+        test("TestFunctionsInSameFileAreMangled", testFunctionsInSameFileAreMangled)
+    }
+}