Add makefile targets bin/tracer-runtime.js and bin/traceur-runtime.min.js

Also target 'concat' to build bin/traceur.js by concatenating bin/traceur-runtime.js and a compile without a runtime.
The concat target can be tested to verify separate compilation.

Review URL: https://github.com/google/traceur-compiler/pull/513

Closes #513.
Change super binding to start with Class.prototype (or Class for statics)

The super calls should start with `Class.prototype` (or `Class` for static methods)

Fixes #511

Review URL: https://github.com/google/traceur-compiler/pull/512

Closes #512, closes #511.
Remove protoParent argument to createClass

Now that super starts with the `Class.prototype` we do not need to keep protoParent in scope. We can therefore remove the argument and just use a local variable inside `createClass`.

Review URL: https://github.com/google/traceur-compiler/pull/514

Closes #514.
Separate test-runtime target, independent of bin/traceur.js

Test name resolution first.
Part of issue #515

Review URL: https://github.com/google/traceur-compiler/pull/516

Closes #516.
New class transformer

This changes how we generate the code for classes.

This is a resurrection of 8da9429 and 5d8db52 with changes to not make the functions hoist.

```js
class C extends B {}
```

now compiles to

```js
var C = function() {
  $traceurRuntime.defaultSuperCall(this, $C.prototype, arguments);
};
var $C = ($traceurRuntime.class)(C, {}, {}, B);
```

Review URL: https://github.com/google/traceur-compiler/pull/517

Closes #517.
export getVariableName from FreeVariableChecker.

Allow derived classes to use this helper function

Review URL: https://github.com/google/traceur-compiler/pull/518

Closes #518.