peerstore: re-export ErrNotFound

This is to avoid having to import ds elsewhere.
spipe + handshake with peerstore
update net with peerstore
ammend tests with changes
increment time for queue test

it's failing when machine slow (travis)
ok fixed queue test
fixed muxer errors
set util.ErrNotFound = ds.ErrNotFound
remove stale TODO
handshake catch
crypto: abstracted Key and added Equals.
Merge pull request #128 from jbenet/feat/peerstorefix

Peerstore Fix
udpated commands and RPC dialing to work with new configuration changes
update readme and a couple comments
Implement ipfs init -d (change datastore location)
Refactor config file location, add IPFS_CONFIG_DIR

Removed config.Filename and replace it with config.GetConfigFilePath that
takes a configuration directory as argument instead. Makes code simpler.
ipfs.getConfigDir now also return the default configuration dir instead of
an empty string in some cases.
Correct style.
Fix error handling
Check the datastore is writeable when initializing
When initializing datastore, create directory with correct permissions.