Update copyright year to include 2019

Fix JDK8 javadoc lint errors

updating project metadata from Google Code to Github transition, fixes #267 (#269)

Issue 255 ; fix assembly mainClass configuration

update scm URLs branches/3.0-spike --> trunk

[maven-release-plugin] prepare for next development iteration

[maven-release-plugin] prepare release piccolo2d-complete-3.0

[maven-release-plugin] prepare for next development iteration

[maven-release-plugin] prepare release piccolo2d-complete-3.0-beta1-rc2

Issue 166 ; refactor PNode moveToBack and related

Issue 252 ; merge build-related changes from trunk to branches/3.0-spike

[maven-release-plugin] prepare for next development iteration

[maven-release-plugin] prepare release piccolo2d-complete-3.0-beta1-rc1

update maven scm to branches/3.0-spike

[maven-release-plugin] rollback the release of piccolo2d-complete-3.0-beta1-rc1

[maven-release-plugin] prepare for next development iteration

[maven-release-plugin] prepare release piccolo2d-complete-3.0-beta1-rc1

updating maven plugin dependency versions and re-arranging reporting sections

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

update version from 2.0-SNAPSHOT to 3.0-SNAPSHOT

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