CTD variable verification

[shaunwbell]

check to see that Tr_904 is in the files it needs to be, same with Trb_980

unify all fluorometry to be Fch_906 (old epic ctd fluorometer was F_903)... Fch_906 is valid for moorings... we are renaming all fluorometer-chlorophyll equivalent to this name

[shaunwbell]

i keep an EPIC key tag in the variables to link back to the intial data format... sorta...