IcyDwarf v14-4-9

Corrected a few bugs and inconsistencies in the Thermal routine: 
-Xhydr[ir] is updated, not (*Xhydr).
-hydrate() can be called as soon as T<Tdehydr_max (rather than
Tdehydr_min). But if the net result is dehydration, then we exit
hydrate() right away and call dehydrate().
-dehydrate() is not called if hydrate() was called and not exited
because of a net dehydration result.