Merging of CTD and bottle salinity and oxygen

[avelo]

Reported by Nico:

This might however be only true for salinity and oxygen .. hence maybe its an error associated with the merging of ctd and bottle values

When exporting the exchange file all values where flags have been changed to 3 or 4 are written as -999, i.e. the original (bad) value is not written to the updated file. However, only the flag should be changed and the value kept....