Switch to getopt

Switch to getopt, feel free to add suggestions. I probably missed many reference in the documentation.

So now it support short (-p), long (--port) version and multiple short `docker run -it ubuntu bash`
Most of the multi letters options we previously have (-no-trunc) only have long version (--no-trunc)

Otherwise it's pretty much the same.

Regarding the help, I think I didn't change the way it works:

`docker --help` or `docker -h` display the usage "daemon mode"
`docker help` display the usage "client mode" (with the list of commands)
`docker help ps` display the usage of docker ps
`docker ps --help` or `docker ps -h` displays the usage of docker ps

@shykes @creack @crosbymichael @keeb please take a look when you have time