writerfilter: drop meaningless WRITERFILTERSTATUS comments

Change-Id: Ief5627c009718c04d8515a0d5510b6c39108f8bc
writerfilter: drop unused BlipDib and FSP in doctok

Change-Id: I900cc3e9b3e7545e141c592183ccd907216832e7
RTF export: fix nested comments

Change-Id: I9986855f3160ed6f5856aec9f7d33fc416962e77