Debugger: Move QT_DECLARATIVE_DEBUG handling out of qdeclarative.h

Debugger: Move QT_DECLARATIVE_DEBUG handling out of qdeclarative.h

Apps don't have to (directly or indirectly) include qdeclarative.h.
Instead, move the static instance to qdeclarativeengine.h, and
qdeclarativeview.h, qsgview.h (which instantiate their own engine).

Change-Id: I8b3e63ad4f134969734a2cc712395145d90e0dfa
Reviewed-on: http://codereview.qt.nokia.com/3941
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Aurindam Jana <aurindam.jana@nokia.com>
Reviewed-by: Martin Jones <martin.jones@nokia.com>