updated tests, moved/removed duplicate functions into methods
Added tests, fixed a number of minor issues and added an additional function to get max value from a field.
Updated table functions, fixed a number of errors in the table schema compare.
Updated to return "NULL" instead of "<Null>" to represent Null value.
Added pretty_print function to table method.
Fixed error in get_multiple_field_value_set function and updated to handle single field passed in
Completed a new function to compare field values with domain values