_NAME_
validate_instrument_id

_PROTOTYPE_
newID = validate_instrument_id(id)

_SHORT-DESCRIPTION_
Check that an instrument ID is valid

_DESCRIPTION_
Check that an instrument ID is valid.  If it is not
valid, but is recognizable, the ID is fixed to the valid
version.  If it is not recognizable, the process exits.

_INPUT_
id is the ID character.

_OUTPUT_
* newID is a valid ID character.  That is, a 'c' (CRIS) or an 's' (SIS).
* If the correct ID cannot be determined, the process exits.