First pass implementation of safe list for ENDER multi-part mime output.
All safe list related changes are ifdef'd MOZ_ENDER_MIME.
Files modified this round:
cmd/xfe/forms.c
include/edt.h
lib/layout/Makefile.in
lib/layout/Makefile
lib/layout/editor.cpp
lib/layout/layfree.c
lib/layout/layform.c
lib/layout/edtbuf.cpp
lib/layout/editor.h
lib/layout/edtlist.h
lib/layout/edtlist.cpp
