Remove 'arch' as an option to --format

My ArchLinux box died so supporting Arch won't be as convenient. Plus it
seems that the Arch users aren't all that 'afraid' to install their own
software manually...
Merge branch 'master' into dev
Fix regex to match tahoe 1.10.0
fix errors in the compatibility checks
tack on http:// to the beginning of node_url if it's missing
get_tahoe_version: tighter regex
work on unittests
raise error if download type not available./ use dict for types
setup.py: check for python  < 3.2 and > 3
updates to tests
repair test
Switch to my site while darrob is away
remove deprecated option warning
tests: add check for introducer with a port
tests: additional version strings to check
Merge branch 'dev' of http://git.repo.i2p/r/grid-updates into dev
documentation updates
add --update and --check-update aliases
update changelog
update compiled manpage