OLE preview: Limit the GDI metafile size to 100000 actions.

Excel can copy huge metafiles to the clipboard, with over 3 million of
actions, which are 1) unusable, and 2) crash LibreOffice because of their
size.

So let's just limit the size of metafiles to be under 100000 actions,
otherwise use the 'OLE' bitmap.

Change-Id: I6a50471e6fe6ab9417592c011bf78cad6247236b
EMF+: Add info about logging.

Change-Id: I72f2c7436df4f1189673d7ccce0d4ac47d338a31
OLE: Turn an OSL_ENSURE() into a real condition.

This is part of some STAMPIT workaround; no idea what it is, but for sure it
causes problems with PowerPoint OLE in Writer - so let's avoid updating if it
is not "STAMPIT".

Change-Id: I266b419ba3461c547f7ee8e447ef64a47a8511e8