update deps URLs to use "tahoe-lafs" instead of bare "tahoe"
Makefile: oops, fix tahoe-deps/tahoe-lafs-deps mismatch

which broke fetch-and-unpack-deps
NEWS: improve highlighting

It looks like github's ReST renderer shows ''' with more emphasis than
---, so use ''' for release names, and --- for groups of changes within
a given release.
NEWS: fix a formatting typo
NEWS: edits, formatting, consolidation, set a date for 1.10.0
known_issues, quickstart: add version and anticipated release date