NEWT MouseEvent: Decouple pointerIds from single-pointer button, i.e. always use proper pointerId >= 0

In case of single-pointer mouse events, always use pointerId 0,
don't derive from button name.

Multiple pointer events still derive button name from the 'action' pointerId.

This allows applications to utilize pointerId equally for single and multiple
pointer events.

Passed all 'junit.run.newt.event' unit tests
Bug 801: LabelButton uses DEFAULT_2PASS_LABEL_ZOFFSET in any mode, due to disabled depth buffer in blend mode
build-test.xml: Handle hs_err_pid*.log files, i.e. clean-up and archive