Made .new private for all Docker::Models, made create a Class method.

This required changing quite a bit of code (mostly specs) that relys
upon making instantiating classes.
More concise names for generated methods.
Updated the README.

Most of the changes relate to the change of `.new` to a private method.
Version bump 1.0.0

Since there was a pretty major interface change (`.new` becoming
private), we think it makes sense to bump it a full major version.
Merge pull request #11 from swipely/make-constructors-private

Make constructors private