Deprecate support for --dockerport flag.

As the result of long standing issues with support for half-close of inbound
TCP connections to Virtual Box guests on (at least) OSX use of port-forwarded
docker connections should be discouraged.

So, if the user really wants to configure it, let them. Otherwise, don't
set it up in the first place.

See boot2docker issue #150 (and others) for details.

Docker-DCO-1.1-Signed-off-by: Jon Seymour <jon.seymour@gmail.com> (github: jonseymour)
closes #204. tested locally
Merge pull request #205 from michaelshobbs/msh-identiesonly

closes #204. tested locally
Merge pull request #153 from jonseymour/150-deprecate-dockerport-flag

Deprecate support for --dockerport flag.
Create driver model and refactor virtualbox dependencies into driver

Conflicts:
	config.go
Small fixes to merge in updates
address gmlewis's nits
Add Travis configuration file
Merge pull request #207 from SvenDowideit/driver-extraction-part2

Driver extraction part2
Update Dockerfile to use the new "golang:1.3-cross" image
rearrange building docs to note that you need go 1.3
Merge pull request #208 from SvenDowideit/13-mention-golang-1.3

rearrange building docs to note that you need go 1.3
Merge pull request #214 from tianon/from-golang

Update Dockerfile to use the new "golang:1.3-cross" image
Exit on driver initialization error
Redirect dummy and virtualbox driver init errors to stderr
Merge pull request #215 from Moghedrin/master

Exit on virtualbox initialization error
Remove the errf and outf utility functions in favor of calling the appropriate fmt functions directly for clearer and more idiomatic code
Merge pull request #191 from tianon/travis

Add Travis configuration file
Merge pull request #217 from Moghedrin/master

Remove the errf and outf utility functions in favor of calling fmt functions