Fixes #14 in main repo. Moves root declaration to build sequence
Added a processing of the CMD in order to use FILE_ACTIVE, FILE_ACTIVE_PATH, etc.
Added the options of using FILE_ACTIVE_NAME and FILE_ACTIVE_NAME_BASE with specs.
Updated readme with newly implemented replacements.
Merge pull request #15 from gpit2286/master

Build: Moves root declaration to build sequence

Solves #14