UnTest v0.4

https://github.com/tenpn/untest/releases/tag/0.4.0

Also creating a basic LICENSE.txt file, so far just references to
third-party lib
ShuffleBagTests
RandomxTests
Vector3ExtensionsTests, plus WithY() bugfix

WithY was returning an erroneous value
Update CHANGELOG.md

v0.1.1 (January 4, 2014)
----

* Documentation improvements.
* Basic testing via UnTest: https://github.com/tenpn/untest
* Fixed: ShuffleBag now correctly removes items as they are used.
* Fixed: Vector3.WithY() was returning bogus vectors.
* Feature: Vector3.Approx(), currently used for internal testing.
Merge pull request #1 from areyoutoo/develop

Merge develop for v0.1.1 release