Add more info about project's intent to README.
Initial bridge.go with lots of TODO.
Partially implement TestBridge_RegisterIn.

Also miscellaneous smaller changes.  Notice that the test does not yet
bind or connect the sockets, and nothing is being properly closed.
Make one test pass.

This is getting a bit hairy.  Of course, encapsulating the complexity is
what this package is for... however, since it now seems I need a
go-routine per out and in/out socket to abstract this properly, it may
make more sense to provide this functionality as a simpler extension of
zmq.Socket.
Rename bridge.go to gzmq.go.
Simplify: per-socket, not per-context.

Following previous commit's suggestion: provide this functionality as a
simpler extension of zmq.Socket.  Some thoughtful work remains to be
done to get this correct, and further work to reduce the number of
goroutines (stack traces are a already bit complex for only two
sockets).
Use another inproc queue for sending.

Prior to this change, the same socket would be used for sending in one
goroutine and receiving in another.
Fix an issue discovered in one environment.

Running tests on Win7x64 with MinGW64 and Go1.0.2, a non-ETERM error is
received right around the time when an ETERM would be expected.  This
fix is to log an error but otherwise respond the same way.
Link to gozmq in README.md.
go fmt
New approach based on polling.

Another overhaul: instead of wrapping sockets, wrap the loop that calls
zmq.Poll().  This way it's just one goroutine even if there are many
channels.  This is getting close to being the minimal work necessary to
bridge sockets and channels.
Add documentation and clean up a bit.
Support sending messages on polled sockets.

It's a bit clunky to have to go through Sync() to do this, but it's good
enough for now.
Add a bit more documentation.
Update README.md and fix a typo.
Use defer to close in tests.
Fix a lingering typo.
Start and Stop instead of just Include.

Rename Include to Start and add Stop (for removing sockets from a
polling).
Add NewSending and Polling.NewSending.

With this change it becomes possible to send messages through Go
channels.  A goroutine is used per such channel, to pump messages into
the corresponding socket.
Add an example.

The documentation is close to useless without one.