Issue 23 ; check for existence of a node before removal to prevent NullPointerExceptions

Issue 19 ; added reference to PCamera as PInputEvent input source in cases where path is null

Issue 17 ; refactoring PCanvas KeyListener to KeyEventPostProcessor

Issue 15 ; properly consume mouse events in PSwing components

added support for non-opaque canvas, see http://groups.google.com/group/piccolo2d-dev/browse_thread/thread/134e2792d3a54cf

Issue 59 ; copyright start year should be 1998 to match oldest files

Issue 59 ; updating license header and adding one where missing

Issue 29 ; Added eclipse formatter configuration, tweaked checkstyle configuration to match, and ran eclipse formatter on the java source in core. Reduced checkstyle errors from 14037 to 2502. Note this commit contains formatting-related changes only, no code changes.

Issue 28; re-adding checkstyle plugin configuration to core, extras, and examples poms, adding sun_checks.xml to src/build/conf in each to enable check configuration

issue#51 aligned package and class names of the tests with the classes under test.

Issue 47; replaced println to stdout/stderr in unit tests with assertNotNull

issue#6 add overview.html to javadocs

issue#44 subdirectory and artifact rename