Remove use of parfor

Also parfor needs to be removed from:

• /Functions/xASL_Iteration line 243
• /External/SPMmodified/toolbox/cat12/cat_surf_epivolsurf.m
• /External/SPMmodified/spm_dcm_fit.m
• /Development/StatsAnalysis/StatTestCompare/StatTrial.m

Release note

Stop using Distributed computing and Parallel Toolboxes and parfor.