misc: Update author information

Author information was added to any file
with the standard license text.
Authors were added that added/changed >= 3%
of the lines of a file.
diff --git a/layers/threading.h b/layers/threading.h
index eb91319..a6fd869 100644
--- a/layers/threading.h
+++ b/layers/threading.h
@@ -19,6 +19,9 @@
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
+ *
+ * Author: Cody Northrop <cody@lunarg.com>
+ * Author: Mike Stroyan <mike@LunarG.com>
  */
 #ifndef THREADING_H
 #define THREADING_H