Add OverlayStackLayout to README, fix license typo, and add to gitignore.

Author: mpaperno

.gitignore

@@ -8,3 +8,6 @@
 build*/
 cmake-build-*/
 *.qmlc
+docs/
+*.tmp
+*.bak

LICENSE.txt

@@ -27,6 +27,6 @@ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 A copy of the GNU General Public License is available in the file LICENSE.GPL.txt
-should be included in this distribution. It is also available at <http://www.gnu.org/licenses/>.
+which should be included in this distribution. It is also available at <http://www.gnu.org/licenses/>.
 
-\endverbatim  */
+\endverbatim  */

README.md

@@ -17,6 +17,9 @@ Project home: https://github.com/mpaperno/maxLibQt
   * `AppDebugMessageHandler` - Custom debug/message handler class to work in conjunction with *qDebug()* family of functions.
 * Item Models
   * `GroupedItemsProxyModel` - A proxy model (`QIdentityProxyModel` subclass) which allows a grouped tree-based item presentation of a flat table data model. Typically used for visually grouping items by some shared criteria, like a category or subject. Useful in a `QTreeView` or the `TreeComboBox` from this collection.
+* Layouts
+  * `OverlayStackLayout` - A QStackedLayout with additional features to allow stacks with "floating" overlay widgets, such as toolbars, buttons, 
+  messages, etc., while still allowing interaction with exposed areas of the widget(s) underneath. Includes a functional image viewer example application.
 * Widgets
   * `ActionPushButton` - A QPushButton which takes a default QAction, just like a QToolButton can.
   * `BuddyLabel` - A QLabel with enhanced "buddy" capabilities like click redirect and tooltip inheritance.