Update copyright year to include 2019

Fix JDK8 javadoc lint errors

Issue 166 ; refactor PNode moveToBack and related

refactoring jdk16 and jdk16-modules back into core and examples respectfully

Issue 148 ; adding PSwingCameraBug to examples.pswing.issues package

Issue 186 ; moving PSwingMemoryLeakExample to examples.pswing.issues package, commit 2 of 2

Issue 186 ; moving PSwingMemoryLeakExample to examples.pswing.issues package, commit 1 of 2

Issue 221 ; adding ZeroWidthStrokeBug to examples.issues

Issue 186 ; moving issue-related examples to examples.issues package, commit 2 of 2

Issue 186 ; moving issue-related examples to examples.issues package, commit 1 of 2

Issue 236 ; adding zoom event handler that responds to mouse wheel events

Issue 235 - PSwingEventHandler now uses Point2D.Double in call to cameraToLocal to avoid under/overflow

- small javadoc change to fix javadoc warnings

Issue 217; adding/replacing license headers

Issue 173; (merge from branch) Introduced useBufferedPainting option to PSwing. Used much of the original buffered painting implementation details from Piccolo2D 1.2. Also added PSwingExample4 which extends PSwingExample1 but turns on buffered painting for all of the PSwing nodes.

Issue 205 ; updating copyright year in license header to 2011

applying doc & style patch from Issue 204

adding full bounds event example

Issue 185 ; applying patch issue185fix.patch

adding reset bounds action

adding text wrapping example

adding animate path example

Issue 185 ; applying patch from atdixon with minor changes, list of activities is cleared after activities are processed

Issue 37 ; refactoring example packages to org.piccolo2d.examples and org.piccolo2d.extras.swt.examples for examples and swt-examples respectively