refactor to encapsulate steps
In the process to generalize this tool, all the procedures and steps has been reviewed (using mainly the lessons learned in the PoC to uprev_piglit_in_mesa. This merge request has been prepared in different commits for each of the elements refactored.
This merge request depends on !37 (merged). The comparison between revisions from where main should be when ready to merge.
Edited by Sergi Blanch Torné