Replaced thor with custom cli solution
 * Actual command are only for demonstration.
Changed dsl language
 * Moved some values from package to top-level definition. This will
   easy some information reusing.
 * Added a source element that will be used to specify information on
   how to fetch the source of the package.
Improved core cli classes
 * Fixed a wrongly named variable in composite.
 * Changed maximum width to 70 when printing text.
 * Added a function to print an error message in base.
Started implementation of some command
 * Command fetch can be used to retrieve source archive.
 * Command extract can be used to extract the archive (and fetch it if
   required).
Bumped development version
 * This release will change the dsl, hence, we bump our version to a new
   major.