Add support for docker-machine and better visualisation of started commands.
Add support for docker-machine and better visualisation of started commands.

This fixes issue #5 .

larskanis/rake-compiler-dock,rake-compiler/rake-compiler-dock,rake-compiler/rake-compiler-dock,rake-compiler/rake-compiler-dock,rake-compiler/rake-compiler-dock,larskanis/rake-compiler-dock,rake-compiler/rake-compiler-dock,larskanis/rake-compiler-dock