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
Show git branch in version output. fixes #1953
Also make sure strings in _version.py are correctly escaped, and repair a test.

Signed-off-by: Daira Hopwood <david-sarah@jacaranda.org>
Merge branch 'master' into truckee

Conflicts:
	NEWS.rst
backout merge of old upstream/1953-branch-in-version
Merge remote-tracking branch 'upstream/1953-branch-in-version' into truckee