Put writing the CGImages behind the env var DBG_WRITE_CGIMAGES

Change-Id: I1eac909bfa0ff3a945c294a2d6f4cb1d454ac985
Introduce drawinglayer::primitive2d::idToString() debugging function

Change-Id: I71e5b032d52f1fe3a1bde60fe6395c5d2d025885
Add a couple of SAL_INFOs using drawinglayer::primitive2d::idToString()

Change-Id: I3fce5ca1af15714b8b20b1b273ccf41a49cb98ff
"Fix" for some SmartArt rendering artefacts on iOS

Exactly why this change works (to the extent that it does) is unclear
to me. Whether it could possibly be used across all platforms and not
for iOS is also unclear.

Change-Id: I6dcf5982d51e5715b657dbf263a88776bbf55f4d
Add MobileCoreServices and ImageIO frameworks for some debugging code in vcl

Change-Id: I6eb0091d22ee5776e9be1bfde76860abc51a69b2