conn_subjects_loader.m: refactor conditions -> groups (new nomenclatura is more correct since conditions are a different concept than subjects groups: conditions are the design experiment elements).
conn_subjects_loader.m: refactor conditions -> groups
(new nomenclatura is more correct since conditions are a different concept than subjects groups: conditions are the design experiment elements).

Signed-off-by: Stephen L. <bede04c5d6a425d8c5798b0cfa1ed9b901b16a3b@gmail.com>

lrq3000/neuro_experiments_tools,lrq3000/neuro_experiments_tools,lrq3000/neuro_experiments_tools