gaston network shift & renaming (gaston -> mn2l-gaston)

cfg/gaston/comp.cfg

-self.pars['CMAKELIST'].val='gaston.cmake'
-self.pars['NB_TASKS'].val='6'
-self.pars['NB_THREADS'].val='1'
-self.pars['RUNMETHOD'].vals=['interactive','at','batch',]
-self.pars['RUNMETHOD'].val='batch'

cfg/gaston/launch.cfg

-self.pars['NB_THREADS'].val='6'
-self.pars['NB_TASKS'].val='1'
-self.pars['RUNMETHOD'].vals=['interactive','at','batch']
-self.pars['RUNMETHOD'].val='batch'