Add more info about project's intent to README.
Initial structure with a failing test.

The test shows that calling conext.SetLinger() with a positive value
does not yet have the intended effect of causing subsequent
context.Close() to return neither immediately (as though linger were
zero) nor before the end of the universe.
Implement SetLinger and Close, tests still fail.
Remove SetLinger and implement Close.

Modified test now passes: sockets are closed when context is closed.
Fix test for SetLinger and make it work.
Merge SetLinger work with clean-up branch.
Describe new features in README.
Use a BSD-style license.
Merge BSD-style licensing.
Implement SetVerbose.
Rename gzmq.go to loop.go.
Merging original loop-like abstraction.
Log SetVerbosity changes.
Correct/update loop tests and fix Context.Close().

The bug on Context.Close() took me a while to track down, so this commit
also brings in a bunch of trace logging.
Modify gzmq_test to allow longer actual linger.

When LINGER was set to 1ms, the SetLinger test would occasionally fail.
This change adds a little extra wiggle room for the test results.
Update README to mention new feature.
Add documentation and emulate "http".

This commit renames PollSocket* methods to resemble Handle and
HandleFunc from the standard "http" module.   It also brings in a few
smaller changes.