Added basic abstractions to CondCode, Gp, and Vec

* Each architecture now provides r32() and r64() functions for
    register casting
  * Each architecture now provides v128() function for register
    casting, returning just Vec to make writing cross platform
    code easier
  * Added some basic condition code abstractions so it can be used
    interchangeably across architectures
  * Added back unlicense to asmjit database (now it's dual licensed)

db/base.js

@@ -1,7 +1,7 @@
 // This file is part of AsmJit project <https://asmjit.com>
 //
 // See asmjit.h or LICENSE.md for license and copyright information
-// SPDX-License-Identifier: Zlib
+// SPDX-License-Identifier: (Zlib or Unlicense)
 
 (function($scope, $as) {
 "use strict";