update README
Merge pull request #201 from rogpeppe/087-fix-README

update README

This should mostly fix issue #160; the one main thing that's omitted
is point 4, because that's not possible to address without mentioning
the private repository.

I am slightly nervous too about introducing a --force-yes option - there's
a reason that unsigned repositories are considered dubious.
update dependencies.tsv
Do not increase download counters if stats=0 is passed.
Merge pull request #203 from frankban/download-counters

Do not increase download counters if stats=0 is passed.
Merge pull request #202 from rogpeppe/088-update-testing-deps

update dependencies.tsv

We want to use the latest version of the testing repository.
all: use local charm testing repo
Merge pull request #204 from rogpeppe/089-local-charm-repo

all: use local charm testing repo

We copy the charms and bundles we need from the charm.v4 repo.

See https://github.com/juju/charm/pull/73
Fix the list of known series.
Merge pull request #205 from frankban/fix-know-series

Fix the list of known series.
Remove the csclient package, now included in another client repo.
Merge pull request #206 from frankban/remove-csclient

Remove the csclient package, now included in another client repo.
internal/v4: add cache-control headers for archive GET
Merge pull request #207 from rogpeppe/090-cache-control

internal/v4: add cache-control headers for archive GET

This will allow the client to know that it can cache the archive files.
internal/router: add fullySpecified parameter to IdHandler

Also add selective caching to internal/v4.
Merge pull request #208 from rogpeppe/091-fully-specified-idhandler

internal/router: add fullySpecified parameter to IdHandler

We also change internal/v4 so that the Cache-Control header is only added when the id is fully specified.
internal/v4, internal/router: use concurrency
Merge pull request #210 from rogpeppe/092-changes

internal/v4, internal/router: use concurrency

This might speed up search results considerably.
internal/v4: add forgotten comment from PR #210
Merge pull request #211 from rogpeppe/093-add-forgotten-comment

internal/v4: add forgotten comment from PR #210

Forgot to write the file before pushing.