Excel config fix

Do not merge before #215 this is an additional fix to the setting file and parsing of integers that @robbiejackson identified and brought to our attention.
This can be added to #215 if needed but I have kept them separate so the last commit can be code reviewed in isolation.

fix settings and errors in three orphan excel file and its associated config/settings.yml file
    
fix orphan import issues identified by @robbiejackson
- Column R (guardian relationship) should be String not Integer
- Column S is integer but has text fields in the excel file that are converted
  to integers (0) because the conversion is too forgiving
- Change parse to integer method that will allow parsing of string integers but
  not of other text
Having looked again at the issue identified by @robbiejackson, I am wondering whether we shouldn't ask for a clarification from the client on this. The value in the fixture for the third record is translated to "pass" by Google - could this mean "N/A", not "password"? Since `guardian_id` is not a required field, would it make sense to be less strict with validations on it, perhaps even going so far as converting it to string?