Allow an explicitly nil :tstart and :tend to suppress the strings.
treedc23150ef071d93c324c6a059ab33faec707dadf
-rw-r--r-- 666 .gitignore
drwxr-xr-x - BUGFIXING
-rw-r--r-- 137595 ChangeLog
drwxr-xr-x - EXPERIMENTAL
-rw-r--r-- 8763 Makefile
drwxr-xr-x - ORGWEBPAGE
-rw-r--r-- 1474 README
-rw-r--r-- 1307 README_DIST
-rw-r--r-- 3475 README_GIT
drwxr-xr-x - UTILITIES
drwxr-xr-x - contrib
drwxr-xr-x - doc
drwxr-xr-x - lisp
-rw-r--r-- 1007 request-assign-future.txt
drwxr-xr-x - xemacs