No need for dirty hacks linking in basegfx objects statically any more.

To avoid unnecessary confusion between the newly plain code and any instance of
the old extension still installed (per-user or shared), I renamed all relevant
UNO implementation identifiers from com.sun.star.comp.documents.* to
org.libreoffice.comp.documents.*.  Also, existing installations of the extension
are explicitly not migrated to new user profiles.

The xpdfimport executable is now in program/, its xpdfimport_err.pdf in
share/xpdfimport/.  To simplify finding the _err.pdf from xpdfimport, its full
pathname is now given as additional second argument to xpdfimport.  To find
xpdfimport executable from CppunitTest, CppunitTest creates a symlink from
solver's unittest/installation/program to solver's bin, so that
"$BRAND_BASE_DIR/program/xpdfimport" works there (as CppunitTest now sets
BRAND_BASE_DIR to solver's unittest/installation).

The sdext/source/pdfipmort/dialogs/ Basic stuff appeared to be unused (even
though it was included in the .oxt) and has been removed.

The --disable-ext-pdfimport configure switch is renamed to --disable-pdfimport.
Having it still conditional requires some pdf_Portable_Document_Format vs.
pdf_Portable_Document_Format_import foo in module filter.

Change-Id: Iee58c2f6187142a418decc9ea3a5df10eb7e0523