wantlist command

make wantlist updates to connected peers happen async

make wantlist updates to connected peers happen async, dramatically improves performance between connected nodes

more understandable errors from merkledag decoding

Add a few tests to fuse/readonly

make the providers manager respect contexts

updated inconshreveable/go-update 

update context imports to golang.org/x/net

- updated go-ctxgroup and goprocess
ctxgroup: AddChildGroup was changed to AddChild. Used in two files:
- p2p/net/mock/mock_net.go
- routing/dht/dht.go

- updated context from hg repo to git
prev. commit in hg was ad01a6fcc8a19d3a4478c836895ffe883bd2ceab. (context: make parentCancelCtx iterative)
represents commit 84f8955a887232b6308d79c68b8db44f64df455c in git repo

- updated context to master (b6fdb7d8a4ccefede406f8fe0f017fb58265054c)

Aaron Jacobs (2):
net/context: Don't accept a context in the DoSomethingSlow example.
context: Be clear that users must cancel the result of WithCancel.

Andrew Gerrand (1):
go.net: use golang.org/x/... import paths

Bryan C. Mills (1):
net/context: Don't leak goroutines in Done example.

Damien Neil (1):
context: fix removal of cancelled timer contexts from parent

David Symonds (2):
context: Fix WithValue example code.
net: add import comments.

Sameer Ajmani (1):
context: fix TestAllocs to account for ints in interfaces

Implement dht put and get CLI commands

fix panic in offline calls of 'ipfs object stat'

Fix Dockerfile

make it easier to create custom dag objects via the CLI

fix fuse reading on linux

update the readme hash in sharness