[Wasm] Add Wasm IR

Intended to be used by Kotlin/Wasm compiler.

Includes:
 * IR tree: declarations, instructions, types.
 * Convertors: ir2text, ir2bin, bin2ir
 * Spec tests, to test convertors against reference Wabt tool

license/README.md

@@ -92,6 +92,11 @@ the Kotlin IntelliJ IDEA plugin:
  - Path: idea/idea-gradle-tooling-api/src/org/gradle/tooling/model/kotlin/dsl
        - License: Apache 2 ([license/third_party/gradle_license.txt][gradle])
        - Origin: Gradle, Copyright 2002-2017 Gradle, Inc.
+       
+ - Path: wasm/ir/src/org/jetbrains/kotlin/wasm/ir/convertors
+      - License: MIT ([license/third_party/asmble_license.txt][asmble])
+      - Origin: Copyright (C) 2018 Chad Retz
+      
 
 ## Kotlin Test Data
 
@@ -220,6 +225,7 @@ any distributions of the compiler, libraries or plugin:
 
 [aosp]: third_party/aosp_license.txt
 [asm]: third_party/asm_license.txt
+[asmble]: third_party/asmble_license.txt
 [boost]: third_party/boost_LICENSE.txt
 [closure-compiler]: third_party/closure-compiler_LICENSE.txt
 [dagger]: third_party/testdata/dagger_license.txt