Deltavision: ignore null lens IDs in the log file

See QA 4758 - 4761.
merge develop -D org -I include -E exclude: PR 159 (Improve .ndpi support)
merge develop -D org -I include -E exclude: PR 351 (Add SPW support to FakeReader)
merge develop -D org -I include -E exclude: PR 424 (Specification changes for 2013-06 release)
merge develop -D org -I include -E exclude: PR 438 (Fix the autogenerated metadata field counts (rebased onto develop))
merge develop -D org -I include -E exclude: PR 439 (Add support for Aperio AFI data)
merge develop -D org -I include -E exclude: PR 443 (Deltavision: ignore null lens IDs in the log file (rebased onto develop))