Removed dependency on `este-library`, added `ReactTestUtils`

Unit tests dont require `este.thirdParty.react` library which allow use
without `este-library`. Added better support for React testing by adding
`React.addons.TestUtils` as a `TestUtils` global variable.
Added native support for `sinon-chai`, `expect` and `should`

At every unit test `expect` or `should`s BDD syntax can now be used.
Chaining style of writing asserts is available for sinon asserts now.
Updated readme