IcyDwarf v14.4.17

-Fixed an inconsistency in the Crack subroutine that stopped crazy
thermal mismatch cracking (Ceres, 2 Myr after CAIs).
-Initialized ircrack to NR rather than 0 (bug) to avoid spurious
hydration/dehydration calculations.
-Reverted to hydrating anytime the temperature is low enough in the
cracked zone in contact with the seafloor, rather than after a time set
by a physical hydration rate.
-Converted all the float variables to type double.