Convert EMFP_DEBUG to SAL_INFO, etc.

* Change to SAL_INFO instead of EMFP_DEBUG in emfplus.cxx
* Use #ifdef OSL_DEBUG > 1 to conditionally compile in debugging routines
* Remove some commented/conditionally compiled out code
* Change logging area for SAL_WARN from cppcanvas to cppcanvas.emf

Change-Id: I6db0021807634070cfa2fee0f07e32d235b3d2f3
Reviewed-on: https://gerrit.libreoffice.org/3782Reviewed-by: Tor Lillqvist <tml@iki.fi>
Tested-by: Tor Lillqvist <tml@iki.fi>