Work around golang.org/issue/4590

Change-Id: Ibde7a93db7dcb8c51eb828b6c4e50505904fce6a
client: cap the number of in-flight requests to 5, for now

keeps camput and the server from running out of file descriptors. will do something
smarter in a subsequent patch.

Change-Id: Icca5027388eb838d45b443b7f2c331ba0f2c6585
camput: move interfaces to their own file

Change-Id: I44276ecd1d3474efeb35308638a317605cedf05a
more TODO

Change-Id: I72e7074a3cc026270685547b9f4019a373a4f6e8
Merge branch 'master' of ssh://camlistore.org:29418/camlistore
vivify: support in camput and upload handler.

no special credentials/auth yet.
pkg/blobserver/handlers/get.go moved to
pkg/blobserver/gethandler/get.go to avoid
a dependency loop with the json sign helper.
pkg/server/sig.go was moved to pkg/jsonsign/signhandler
because it seemed inapproriate to import in
pkg/blobserver/handlers/upload.go something from
pkg/server

Change-Id: Ifeb14512e182e8a101d4fced6d6d4184e2b9cb99
Merge "vivify: support in camput and upload handler."
client: fix blobserver path in curl and python clients

Change-Id: Ie7a204ee64a9373c696e447ccf93a790584676d6
Merge "client: fix blobserver path in curl and python clients"