* Remove _isAttached member var and isAttached method
* Engines now always call the onFrame method; whether it does
something is decided by the debugger class resp. its subclasses
* Make detach() protected instead of private, so that subclasses
can invoke it
* Remove _detach_now member var (call detach() instead).
* Rename _frame_countdown to _frameCountdown and properly
document it.
* Add more doxygen comments
* Cleanup
svn-id: r50963
1d4c82885d