* more nuanced subs / slice error message

* fixes ticket 913

* updated release date in ../4.0.5.txt and the debian change log to O…

…ctober 19th.

* update release date for 4.0.4

* updating versions and dates for 4.0.3

* updating other version places

* update release notes for tickets 640 and 641

Fix condition in Makefile.gnu when HG is empty, force it to be 'hg' e…

…ven though the command will fail. mkver has failsafes in place for this condition.