refactor: move rtts-assert into modules directory

The rtts assertion lib is only needed for js, 
but it should be treated like any other module (e.g. facade, …)

modules/rtts_assert/API.md

@@ -0,0 +1,44 @@
+// Asserting APIs:
+// - generated by Traceur (based on type annotations)
+// - can be also used in tests for instance
+assert.type(something, Type);
+assert.returnType(returnValue, Type);
+assert.argumentTypes(firstArg, Type, secondArg, Type);
+
+// this can be used anywhere in the code
+// (useful inside test, when we don't wanna define an interface)
+assert(value).is(...)
+
+
+// Custom type assert:
+// - i have a custom type
+// - adding an assert methos
+assert.define(MyUser, function(value) {
+  assert(value).is(Type, Type2); // or
+  assert(value, 'name').is(assert.string);
+  assert(value, 'contact').is(assert.structure({
+    email: assert.string,
+    cell: assert.string
+  }));
+  assert(value, 'contacts').is(assert.arrayOf(assert.structure({email: assert.string})));
+});
+
+
+
+// Define interface (an empty type with assert method)
+// - returns an empty class with assert method
+var Email = assert.define('IEmail', function(value) {
+  assert(value).is(String);
+
+  if (value.indexOf('@') !== -1) {
+    assert.fail('has to contain "@"');
+  }
+});
+
+
+// Predefined types
+assert.string
+assert.number
+assert.boolean
+assert.arrayOf(...types)
+assert.structure(object)