Fix package doc
Fix package doc

- The package documentation must not be separated from the package
  declaration by blank lines.
- The godoc convention is to follow the pattern "Package <name> ...".
- The statement about go-dockerclient is wrong for some time now, and
  refers to an implementation detail, not fundamental to explain the
  purpose of the package.

jim-minter/source-to-image,dobbymoodge/source-to-image,gabemontero/source-to-image,PI-Victor/source-to-image,liggitt/source-to-image,csrwng/source-to-image,PI-Victor/source-to-image,csrwng/source-to-image,coreydaley/source-to-image,guangxuli/source-to-image,openshift/source-to-image,soltysh/source-to-image,bparees/source-to-image,rhcarvalho/source-to-image,mfojtik/source-to-image,openshift/source-to-image,jim-minter/source-to-image,soltysh/source-to-image,dobbymoodge/source-to-image,liggitt/source-to-image,PI-Victor/source-to-image,gabemontero/source-to-image,coreydaley/source-to-image,mfojtik/source-to-image,jim-minter/source-to-image,bparees/source-to-image,gabemontero/source-to-image,rhcarvalho/source-to-image,liggitt/source-to-image,guangxuli/source-to-image,bparees/source-to-image,rhcarvalho/source-to-image,gabemontero/source-to-image,soltysh/source-to-image,dobbymoodge/source-to-image,mfojtik/source-to-image,csrwng/source-to-image,csrwng/source-to-image,jim-minter/source-to-image,dobbymoodge/source-to-image,rhcarvalho/source-to-image,liggitt/source-to-image,guangxuli/source-to-image,guangxuli/source-to-image,coreydaley/source-to-image,openshift/source-to-image,soltysh/source-to-image,coreydaley/source-to-image,mfojtik/source-to-image,PI-Victor/source-to-image,bparees/source-to-image