Merge pull request #168 from kealjones-wk/AF-361-react-wrappers-top-level-lib

AF-361: Adds top level react_wrappers lib and removes test_util.react_util lib

Author: aaronlademann-wf

test/test_util/react_util.dart lib/react_wrappers.darttest/test_util/react_util.dart renamed to lib/react_wrappers.dart

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-library test_util.react_util;
+/// Utilities for handling `over_react` wrapped react components.
+library over_react.react_wrappers;
 
 export 'package:over_react/src/util/react_wrappers.dart';