manage global/environment variables differently
environ.py has been completely rewritten to provide a proper singleton class to store the variables (TMP_DIR, ROOT_DIR. etc..) The user view of the environment is a dictionnary, cf #121 (closed) user story
This MR can be completed after team discussion and approval on the design.
P.S.: the change of *.ini content as described in #121 (closed) has not been coded. For now, this NR only contains the refactoring with same funcitonnalities.
Edited by SZPYRKA Jean-Luc