Merge pull request #98 from michaloo/master

Change `env-file` parameter type from string to array
pass config to the commands function for more flexibility
make Config an interface
make it explicit that we get targeted containers only
expose the dependency graph as a fresh struct
expose Dependencies fields
Merge pull request #93 from bjaglin/pregraph

Refactoring
Remove --target option
Merge unmarshal functions
Remove containerMap type
Improve documentation
graph command
highlighting via target
fix support for multiple-arguments, string `cmd`
Add test for string commands with multiple parts
Bump version to 0.10.0