Add hamming distance calculation to bloom filters

add more bitswap task workers

changed IPFS_TASK_WORKERS to IPFS_BITSWAP_TASK_WORKERS

increase window size for yamux streams

README: alpha version has been released

move log messages out of warning level

secio: better error detection

The same keys + nonces in secio were being observed. As described in
https://github.com/ipfs/go-ipfs/issues/1016 -- the handshake must
be talking to itself. This can happen in an outgoing TCP dial with
REUSEPORT on to the same address.

Fixed broken http link in README.md

Markdown didn't have "http://" so the link returned 404

Fix hub.docker.com URL

Added documentation for docker usage. 

log listeners dying as at least a warning

fix ugly error message when killing commands

Publish by path

updated goprocess to deal with memory leak

bugfix: add was not setting error

corehttp: added support for HEAD requests

This commit adds HEAD support to the IPFS Gateway.
Related: #840

reuseport: env var to turn it off

reuseport is a hack. It is necessary for us to do certain kinds of
tcp nat traversal. Ideally, reuseport would be available in go:

  https://github.com/golang/go/issues/9661

But until that issue is fixed, we're stuck with this. In some cases,
reuseport is strictly a detriment: nodes are not NATed. This commit
introduces an ENV var IPFS_REUSEPORT that can be set to false to
avoid using reuseport entirely:

  IPFS_REUSEPORT=false ipfs daemon

This approach addresses our current need. It could become a config
var if necessary. If reuseport continues to give problems, we should
look into improving it.

Fix various issues in the test makefiles