Added Docker::Container#run.

This method will allow for some pretty clean Container chaining.
In addition to this method, I also added #start?, #stop?, #kill?,
and #restart methods to the Container which will attempt to run those
methods, but rescue from any Server errors. Essentially, this means it
will try to run those methods unless the Container is in an invalid
state.
Added support for streaming Docker::Container#attach.
Version bump 1.2.0
Dockerfile => Docker

oops.
Now using octal for file permissions, simplified Docker::Image#remove.
Cleaned up Docker::Container#run.

It no longer has a default amount of time to wait to finish executing.
Some minor house keeping.

Docker::Container#commit now uses Docker::Util.parse_json; shortened a couple of requests.
Back to a timeout of 1000 seconds :(:(:(.

Unfortunately, Excon does not allow an inifinite read timeout -- or at
least not through any means I could find.
Fixed a comment typo
Merge pull request #16 from swipely/add-container-run

Add container run