Changed the Timed Automata model for reactant-centered: when exiting
from the "not_reacting" location, the clock is not reset; while the
permanence in "not_reacting" stops the clock from increasing (c'==0).
Added a Cytoscape network option "useOldResetting": when true, the older
model will be used, using the reset (c:=0) when exiting from
"not_reacting".