Allow for arbitrary root namespace in SkippyLib

[thomthom]

Instead of a fixed SkippyLib namespace for libraries, allow for user defined namespace:

module SkippyLib
  class Command
  end
end # module

module TT_Lib
  class Command
  end
end # module

To make it easier to rewrite the namespace, this must be defined in skippy.json:

{
  "library": true,
  "name": "tt-lib",
  "namespace": "TT_Lib",
  "version": "3.0.0",
}